Hyster A186 Service Manual - PDF DOWNLOAD

INTRODUCTION GENERAL This section has the description, operation, checks and adjustments for the parts of the electric power steering (EPS) system. The system electrically controls a motor to turn the master drive unit for steering. This section is NOT for lift trucks that have the wire guidance system.

See the sections WIRE GUIDANCE, DESCRIPTION, 2200 SRM 317, section to adjust or WIRE GUIDANCE, REPAIR, 2200 SRM 321, to repair the parts of the EPS system used on lift trucks with wire guidance.

to turn the drive sprocket. The drive sprocket moves the chain to turn the MDU on the spindle. The steering potentiometer is turned by a gear on the MDU spindle.

The potentiometer tells the ECM the position of the MDU.

DESCRIPTION (See FIGURE 1.)

The electric power steering system has no cables or hydraulic lines between the steering wheel and the Master Drive Unit (MDU). The system uses electrical signals to control an electric motor and gear box to turn the MDU. An electrical signal generated by turning the steering wheel is an input to a control module that operates the motor. Other inputs are also used for correct steering control.

The following parts are in the system: a. Steering wheel, gears and steering generator b. Two wires in an 18 conductor cable between the steering generator and electrical compartment c. The Electronic Control Module (ECM) d. The electric motor, worm reduction gear and chain to the MDU e. The steering potentiometer f. The automatic shut–off card.

The speed and direction of rotation of the steering wheel sets the voltage and polarity of the generator signal. The generator signal varies from zero to a plus voltage and from zero to a minus voltage to indicate steering rate and direction. The steering wheel and gears turn the shaft of the signal generator. The ECM uses the inputs from the steering generator and steering potentiometer to control the power to the steering motor.

The ECM is fastened to the electrical compartment door or panel. The door or panel is a heat sink for the module. The steering motor is a permanent magnet motor. The steering motor turns the worm reduction gear

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MULTIPLE CONDUCTOR CABLE STEERING WHEEL STEERING GENERATOR TRACTION CIRCUIT AUTOMATIC SHUT–OFF CARD ELECTRONIC CONTROL MODULE BATTERY STEERING MOTOR AND GEAR BOX STEERING POTENTIOMETER MDU AND CHAIN

FIGURE 1. ELECTRIC POWER STEERING PARTS

OPERATION Rotation of the steering wheel turns the gears and the steering generator shaft. The generator voltage, indicating the direction and rate of rotation, goes to the electronic control module (ECM). The ECM knows the position of the MDU from the signal of the steering potentiometer. The ECM sends a signal to the steering motor to turn the MDU. The steering potentiometer checks that the MDU moves correctly.

If the MDU does not move correctly, the ECM sends a signal to the automatic shut–off board. The automatic shut–off circuit sends a signal to the traction control circuit. The signal will deenergize the traction circuit and apply the brake. After shut–off occurs, the system must be reset by moving the key to the OFF position.

Energize the electrical system to continue operation.

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CHECKS, ADJUSTMENTS AND TEST PROCEDURES GENERAL

NOTE: The ECM display will show an “E” if the automatic shut–off circuit has operated to prevent lift truck movement.

WARNING Many checks and adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. During some checks or adjustments the operator must move the truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the truck to cause an injury.

The EPS system uses the ECM test circuit to check for correct operation and adjustment of the parts of the system. The test circuit automatically makes some checks during operation. Other checks can be done manually.

These last checks are normally necessary as part of the adjustment procedures. The checks are found in the ADJUSTMENTS and TEST PROCEDURES of this section. The Test push button, on the ECM circuit board, is used to change to the next manual test. The display, LED 1 and LED 2, on the ECM circuit board, indicate the results of the tests. See FIGURE 2. The ECM test circuit has the following sequence for the the manual tests: 1 and 2.

Automatic Checks The logic system of the ECM makes internal checks for correct operation. The checks are automatic and occur during steering.

Program Memory Checksum This automatic test checks the program memory of the ECM each time the guidance system is energized.

During the first half–second after the electrical system of the lift truck is energized, the display will show an “F”. If the display shows a “C”, the contents of the memory are not correct. The steering system will not operate and the system program needs a correction. Reset the system by moving the key to the Off position, then back to the On position. If the display again shows a “C” when the system is energized, replace the ECM logic board. The display will show the numbers as described in Normal Display if there is no “C”.

Watchdog Reset

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1. DISPLAY 2. TEST BUTTON

3. LED 1 4. LED 2

FIGURE 2. ECM CIRCUIT BOARD

CHECKS The following paragraphs have a description of the automatic checks that are done by the test circuit of the ECM. There is also a description of the numbers and letters on the ECM display during normal operation.

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This automatic test checks for faults that can reset the ECM. These faults normally occur only once. The lift truck will continue to operate and the display will show an “8” to indicate a possible problem. The “8” display can be a guide to the service person if a malfunction does not occur at a regular interval. The fault can be a temporary poor connection.

Normal Display The display will show one of the following numbers during normal operation.

0 – The steering wheel is not turning.

NOTE: The following display numbers are constantly changing. Read the average number.

1 or more – The operator is turning the steering wheel (display number times 6.25 is the steering motor current).

ADJUSTMENTS

Adjustment of the Steering Chain (See FIGURE 3.)

General NOTE: Never adjust the EPS system if the system operates correctly.

WARNING Some of the adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. These metal items can accidently make an electrical connection and cause an injury.

WARNING During some of the adjustments, the operator must move the lift truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the lift truck to cause an injury.

1. Open the electrical compartment doors and make sure the MDU is in position for straight travel. Make sure the steering chain is tight on the section of chain near the battery.

2. Operate the steering to find the point where the steering chain has the least clearance. Move the steering wheel to turn the MDU to the full CW position. Slowly turn the MDU in the CCW direction and watch the steering chain. The point of least clearance is the point where the steering chain is straight or nearly straight between the sprockets.

1.3 TO 3.3 mm (0.05 TO 0.13 in)

A malfunction of a separate part in the steering system can prevent correct electrical adjustment of the EPS system. All parts must be installed correctly and checked for correct operation.

SET UP PROCEDURES FOR EPS During the adjustment and test procedures, you will have instructions to set the lift truck or lift truck system for different functions. The following are the correct procedures: To Energize The Lift Truck Electrical System: a. Connect the battery to the lift truck. b. Make sure all gate, side rail or brake switches are closed. Move the key switch to the ONand START positions.

To Deenergize The Lift Truck Electrical System: a. Disconnect the battery from the lift truck. Separate the battery connector. b. Discharge all capacitors on the lift truck that remain charged after disconnecting the battery.

These capacitors can be capacitor 1C in the SCR traction and hydraulic control systems.

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1. REDUCER SPROCKET 2. STEERING CHAIN 3. MDU SPROCKET

4. ADJUSTING NUT 5. ADJUSTING BOLT 6. RIGID MATERIAL

FIGURE 3. ADJUSTING THE STEERING CHAIN 3. Install a thin piece of rigid material on the chain between the sprockets. The material must have a straight edge. Make sure the chain is tight on the opposite side of the sprockets. Measure the clearance between the bottom of the straight edge of the rigid material and the chain. See FIGURE 3. The middle of the chain must have a clearance of 1.3 to 3.3 mm (0.05 to 0.13 in).

a. Energize the lift truck electrical system.

4. Tighten the adjusting nut at the MDU sprocket for a maximum clearance of 1.3 to 3.3 mm (0.05 to 0.13 in) between the chain and straight edge. Do NOT tighten the adjusting nut for a clearance of less than 1.3 mm (0.05 in).

b. Push the Test button on the ECM circuit board.

5. Close and fasten the electrical compartment doors.

To Energize The Manual Test Function:

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TORQUE 122 to 136 N.m (90 to 100lbf ft)

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1. STEERING POTENTIOMETER 2. BRACKET, POTENTIOMETER 3. MOUNT SCREWS FOR POTENTIOMETER 4. MDU GEAR

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POTENTIOMETER PINION STOP SCREW LIMIT SWITCH LS7 LIMIT SWITCH LS5

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LOCK NUT BRAKE DRUM SIDE PLATE BRACKET ASSEMBLY

FIGURE 4. STEERING POTENTIOMETER AND LIMIT SWITCH ADJUSTMENT Adjusting Limit Switches (See FIGURE 4.)

Adjustment of the Steering Potentiometer (See FIGURE 4. and FIGURE 6.)

1. Align the MDU by measuring the distance between the brake drum and the frame side plate on each side of the brake drum. See FIGURE 4. Adjust the MDU so that these measurements are equal. Use a large screwdriver to turn the armature shaft of the steering motor to align the MDU.

1. Align the MDU by measuring the distance between the brake drum and the frame side plate on each side of the brake drum. See FIGURE 4. Adjust the MDU so that these measurements are equal. Use a large screwdriver to turn the armature shaft of the steering motor to align the MDU.

2. Use washers to align the limit switch and potentiometer bracket. The limit switch rollers and the potentiometer pinion gear must be aligned with the MDU gear weldment.

3. If necessary, bend the tabs on the lock washer to loosen the lock nut to move the gear weldment. Align the gear weldment and tighten the lock nut to 68 to 102 N.m (50 to 75 lbf ft) torque. Do not let the gear weldment or MDU move as the lock nut is tightened.

4. Bend at least one tab of the lock washer into the hole of the gear weldment and one tab into the lock nut.

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2. Energize the lift truck electrical system. Push the Test button on the ECM. Make sure there is a “2” on the display.

3. If the ECM has an R58 potentiometer, adjust R58 for a flashing LED 2 on the ECM board. If the ECM does not have an R58 potentiometer, rotate the steering potentiometer housing for this adjustment.

NOTE: Do not touch the terminals on the steering potentiometer while making adjustments. Touching the terminals will cause an incorrect reading.

NOTE: If the results are not correct for step 3, do step 4.

4. Rotate the steering potentiometer housing to the center position of the adjustment range of the mount.

5. Push the Test button on the ECM for a “2” on the display. Loosen the stop screw for the steering potentiometer. Move the steering potentiometer away from the drive gear. Rotate the potentiometer pinion for a flashing LED 2. Engage the pinion. Adjust the stop screw for a clearance of 0.8 to 1.0 mm (0.030 to 0.040 in) at the point of minimum clearance. Repeat step 3.

age. Clean the battery and battery compartment as necessary. There can also be a voltage on the frame if there is carbon dust in the motors. Use dry compressed air to remove the carbon dust from all motors.

TEST PROCEDURES

There are two procedures to check for correct operation of the component. The first check uses the manual test of the ECM test circuit. The second procedure uses a digital voltmeter.

Checking For Short–Circuit To Frame General It is important for the correct operation of the EPS system that all system components have electrical insulation. There must be electrical insulation between the frame of the lift truck and each component. If a connector, cable, wire or component is making a connection to the frame, a malfunction can occur. The position of a motor cable can make a magnetic field that can change the the signals to the ECM. Electrical static can also cause a malfunction. Make sure all cables are installed in the same position that they were in before removal.

Make sure all shields are correctly installed and connected. Make sure all insulation and isolators are correctly installed. Repair all short–circuits as soon as they are found. Keep the battery and battery compartment clean and painted. Keep all carbon dust and dirt removed from the inside of all the motors. Use dry compressed air.

Steering Generator Checks

ECM Manual Test: NOTE: The steer wheel will not move during this test.

Energize the the electrical system and push the Test button for a “1” on the ECM display. Make sure LED 1 is On and LED 2 is Off. Have the operator turn the steering wheel to steer the lift truck in the 9:00 clock direction first. Then, turn the steering wheel for a turn in the 3:00 clock direction. See FIGURE 5. This sequence of steering wheel rotation must be followed.

LED 1 must be Off and LED 2 must be On when the lift truck steers toward the 9:00 clock direction. LED 1 and LED 2 must both be On for the 3:00 clock direction. If the results are not correct, move the key to the OFF position to reset the system and do the Voltmeter Check.

LOAD WHEEL

Checks 1. To check for wire connections to the frame, disconnect the battery. Use an ohmmeter to check the circuits.

Check for 50,000 ohms or more between each terminal of the battery connector for the lift truck and a clean connection on the frame. Make sure there are no electrical connections to the frame of the lift truck. Wires or terminals without insulation can cause these connections.

2. Check for voltage between each terminal of the connector to the battery and a clean metal connection on the frame of the lift truck. It is normal to measure some voltage between the battery and the frame even if the resistance checks are correct. There can be a voltage on the frame if the battery is dirty or the battery has dam-

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STEER WHEEL FIGURE 5. LIFT TRUCK DIRECTION ORIENTATION

Voltmeter Check: The following tests can be made at both the steering generator and at the ECM board. Do the checks at the 5

ECM board first. If the tests at the ECM board are correct, the steering generator and the wiring to the ECM are good.

of 4 to 5 volts. The voltage will be positive in one direction and negative in the other direction. If the voltage readings are not correct, do the same checks at the steering generator. If the voltage readings are correct at the generator but not the plug, check the wires and connections. If the voltage is not correct in step 1 and is correct in this step, replace the logic board.

1. Energize the electrical system. Connect the positive voltmeter lead to TP4 on the ECM board. Connect the negative voltmeter lead to TP9 on the ECM. When the steering wheel is not being moved, the correct voltage is 2.5 volts. Turn the steering wheel quickly to steer the lift truck in the 9:00 clock direction. The correct voltage reading is a positive (+) 5 volts. Turn the steering wheel quickly to steer the lift truck in the 3:00 clock direction. The correct voltage reading is 0 volts. If the voltage readings are not correct, do step 2.

Electronic Control Module (ECM) General The ECM must have the correct supply voltage and the fuses must be good for correct operation of the ECM. Other checks for the ECM are checks for correct inputs and outputs. FIGURE 6. has the location of the parts on the ECM board. Check FIGURE 6. when making checks and adjustments on the ECM board.

2. Disconnect the battery connector. Connect the voltmeter leads between terminals 4 and 5 at ECM plug B. Turn the steering wheel in one direction, then the other.

When the steering wheel is turned rapidly, the voltage will increase. The voltage varies with the speed of steering wheel rotation. The voltage can be a maximum 1

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1. Check for battery voltage between terminal 4 (–) and 1 (+) on the power terminal strip.

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AUTO SHUT–OFF STEERING GENERATOR STEERING GENERATOR STEERING POTENTIOMETER STEERING POTENTIOMETER STEERING POTENTIOMETER (+)

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DISPLAY TEST BUTTON LED 1 LED 2 R58 POTENTIOMETER POWER TERMINALS 1 – BATTERY POSITIVE (+) 2 – STEERING MOTOR 3 – STEERING MOTOR 4 – BATTERY NEGATIVE (–)

7. FUSE 2 (20 AMP S.B.) 8. FUSE 1 (1 AMP S.B.) 9. TEST POINTS TP1 – COARSE STEER WHEEL ANGLE TP2 – FINE STEER WHEEL ANGLE TP3 – STEERING MOTOR CURRENT TP4 – STEERING GENERATOR TP9 – BATTERY NEGATIVE

FIGURE 6. ECM CIRCUIT BOARD 2. Check that FU1 and FU2 are both good. These fuses are on the power board for the ECM near the power ter6

minal strip. Make sure the key switch is in the OFF

position. Use an ohmmeter to check for a open circuit across each fuse.

Test Button, Display and LED’s On The ECM NOTE: When using the Test button, make sure the circuit has time to operate on the commands. Push and hold the Test button. Then, release the button to make sure the display changes.

Checks Energize the electrical system. Energize the ECM test circuit. Push the Test button for each of the two tests.

Make sure the display changes correctly and the LED’s illuminate correctly. Replace the ECM board if the display, LED’s or Test button do not operate correctly.

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1. DISPLAY 2. LED 1 AND LED 2 3. TEST BUTTON

FIGURE 7. TEST BUTTON, DISPLAY AND LED’S Steering Potentiometer Checks There are two procedures to check for correct operation of the component. The first check uses the manual test of the ECM test circuit. The second procedure uses a digital voltmeter.

ECM Manual Test: a. Energize the electrical system. Use the steering wheel to move the steer wheel in the position for straight travel. Push the Test button for a “2” on the ECM display. Have the operator turn the steering wheel to steer the lift truck in one direction and then in the other direction. The steer wheel must move through the position for straight travel. LED 1 must be On and LED 2

must be Off or LED 2 must be On and LED 1 must be Off. The LED that is On must go OFF as the steer wheel goes through the position for straight travel. The operator can check the steering indicator for the straight travel position. If the results are not correct, move the key to the the Off position to reset the system. Do the Voltmeter Check.

Voltmeter Check: The following tests can be made at both the steering potentiometer and at the ECM board. Do the checks at the ECM board first. If the tests at the ECM board are correct, the steering potentiometer and the wiring to the ECM are good. a. Energize the lift truck electrical system. Connect the negative (–) voltmeter lead TP9 on the ECM board. Connect the positive (+) voltmeter lead to terminal 1 at the ECM connector (plug A). The correct reading is 5 volts. Connect the positive lead to terminal 3 (plug A). The correct reading is 0 volts. If the readings are not correct, the problem is in the ECM board or other steering system parts. If the readings are correct, do step b.

NOTE: Make sure the steering potentiometer is adjusted correctly. b. Connect the positive lead to terminal 2 (plug A).

The correct reading is 2.5 volts when the steer wheel is in the position for straight travel. Move the steering wheel to steer the lift truck for a maximum turn in the 9:00 clock direction. The correct reading is 3.75 volts. Move the steering wheel fully to steer the lift truck in the 3:00 clock direction. The correct reading is 1.25 volts. If the readings are not correct, do step c. c. Connect (+) meter lead to the connection for wire 101 at the steering potentiometer. The correct reading is 5 volts. Connect the (+) meter lead to the connection for wire 103 at the steering potentiometer. The correct reading is 0 volts. If either of the readings are not correct, the wire or wires are bad. d. Use the steering wheel to move the steer wheel in the position for straight travel. Connect the positive meter lead to the connection for wire 102 at the steering potentiometer. The correct reading is 7

2.5 volts. If the voltage reading is not correct, the potentiometer is bad.

LOAD WHEEL

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STEER WHEEL 11585

FIGURE 8. STEERING POTENTIOMETER CHECKS Steering Motor Check The Steering Motor Voltage Using a Digital Voltmeter: a. Energize the electrical system. Connect the leads of the voltmeter between terminals 1 (+) and 4 (–) at the power terminals of the ECM board. The correct reading is battery voltage. Connect the voltmeter leads between terminals 2 and 3 at the power terminals. Check the voltage as the steering wheel is turning. The correct voltage is 0 to 6 volts less than the voltage between terminals 1 and 4. Stop turning the steering wheel and check for 0 volts between terminals 2 and 3. If the voltages are correct and the steering motor does not move, do step b. If the voltages are not correct, check the wiring to the ECM. b. Connect the leads of the voltmeter to the steering motor terminals. Move the key to the ON position. Check the voltage as the steering wheel is turning. The correct voltage is 0 to 6 volts less 8

than battery voltage. If the voltage is correct and the motor does not move, replace the steering motor.

Check The Steering Motor Current Using The ECM Manual Test: NOTE: The following display numbers are constantly changing. Read the average number.

Energize the lift truck electrical system. Have the operator move the steer wheel in the position for a maximum turn in either direction. Check the display as the operator rotates the steering wheel as fast as possible for a turn in the opposite direction. To get the steering motor current, multiply the display number by 6.25. A display number of 7 is above the maximum current allowed. The maximum current is 42 ampere.

Check The Steering Motor Current Using The Digital Voltmeter: NOTE: The following display numbers are constantly changing. Read the average number.

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FIGURE 9. STEERING MOTOR VOLTAGE CHECKS Energize the lift truck electrical system. Connect the negative (–) meter lead to TP9 on the ECM board. Connect the positive (+) meter lead to TP3 on the ECM board. Have the operator move the steer wheel in the position for a maximum turn in either direction. Check the voltmeter as the operator rotates the steering wheel as fast as possible for a turn in the opposite direction.

To get the steering motor current, multiply the number that appears on the voltmeter by 10. The maximum voltmeter reading is 4.2. The maximum current is 42 ampere.

1. To check operation with an open circuit in the steering generator circuit, disconnect the battery connector.

Remove wire 104 or 105 at terminal 4 or 5 (Plug B). Do NOT connect both wires. Install tape on the wire to prevent a short–circuit.

Automatic Shut–Off Circuit

3. To check operation with an open circuit in the steering motor circuit, disconnect the battery connector.

Disconnect wire 122 or 123 from the ECM terminal strip. Do not disconnect both wires. Install tape on the wire to prevent a short–circuit.

The automatic shut–off circuit must prevent lift truck operation for the following malfunctions: Open circuit in the steering generator circuit Open circuit or reversed leads in the steering motor circuit Open circuit or reversed leads in the steering potentiometer circuit Steer wheel steering in the wrong direction

2. Connect the battery and energize the lift truck electrical system. Check that the traction and steering systems do NOT operate. If the systems operate, the automatic shut–off circuit has damage. Replace the circuit board. If the systems do NOT operate, install the wire.

4. Connect the battery and energize the lift truck electrical system. Check that the traction and steering systems do NOT operate. If the systems operate, the automatic shut–off circuit has damage. Replace the circuit board. If the systems do NOT operate, install the wire.

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FIGURE 10. CHECKING AUTOMATIC SHUT–OFF CIRCUIT

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FIGURE 11. TEST POINT CHECKS

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5. Check for operation with reversed leads to the steering potentiometer and for steering in the wrong steering direction. Disconnect the battery connector. Temporarily move the wire from terminal 1 to terminal 3 and the wire from terminal 3 to terminal 1 (plug A).

6. Connect the battery. Check that the traction and steering systems do NOT operate. If the systems operate, the automatic shut–off circuit has damage. Replace the circuit board. If the systems do NOT operate, install the wires on the correct terminals.

Test Point Checks The following voltage readings are taken at the three test points (TP) on the ECM board. Connect the negative (–) meter lead to TP9.

Connect the negative lead of the digital voltmeter to TP9 for all of these checks. Put the positive lead on the correct test point for each test.

TP1 – The correct reading is 2.5 volts when the steer wheel is in the position for straight travel. When the steer wheel is fully toward a turn in the 9:00 clock direction, the correct reading is 0 volts. When the steer wheel is fully toward a turn in the 3:00 clock direction, the correct reading is 5 volts.

TP2 – The correct reading is 2.5 volts when the steer wheel is in the position for straight travel. When the steer wheel is 16° toward a turn in the 9:00 clock direction, the correct reading is 0 volts. When the steer wheel is 16° toward a turn in the 3:00 clock direction, the correct reading is 5 volts.

TP3 – The voltage reading times 10 is the steering motor current.

TP4 – The correct reading is 2.5 volts for no steering action. When turning the steering wheel quickly in one direction, the correct reading is 0 volts. When turning the steering wheel quickly in the other direction, the correct reading is 5 volts.

REPAIR WARNING To help prevent injury, never have any metal on your fingers, arms or neck when using these repair procedures.

nuts that fasten the steering generator assembly to the instrument panel. Remove the assembly.

4. Remove the screw and intermediate gear from the hub plate.

STEERING GENERATOR (See FIGURE 12.)

5. Remove the three screws and washers that fasten the generator to the hub plate. Remove the generator.

Install the replacement generator on the hub plate.

1. Disconnect the battery connector so that it is completely free. Remove the cover at the operator platform for an access to the terminal strip at the instrument panel.

6. Install a thin coating of LoctiteR 290 or equivalent on the threads of the screw for the intermediate gear.

Install the intermediate gear and screw on the hub plate. Tighten the screw to 2.3 N.m (20 lbf in) torque.

2. Disconnect the two wires from the steering generator at the terminal strip.

7. Install the assembly on the instrument panel. Connect the generator wires to the terminal strip. If necessary, see the section DIAGRAMS, 8000 SRM 238.

NOTE: Earlier units have a steering wheel held to a tapered shaft with a key and nut. It can be necessary to use a steering wheel puller on these units.

3. Use a wrench on the flats of the shaft and turn the steering wheel counterclockwise to remove the steering wheel. Remove the four capscrews, washers and

NOTE: On earlier units, install the steering wheel using the key, washer and nut.

8. Install a thin coating of LoctiteR 290 or equivalent on the threads of the shaft for the steering wheel. Hold the shaft and install the steering wheel.

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STEERING WHEEL INSTRUMENT PANEL HUB PLATE BEARING SHAFT SEAL BEARING SNAP RINGS SPACER LARGE GEAR SHAFT KEY WASHER LOCK WASHER NUT PINION GEAR STEERING GENERATOR INTERMEDIATE GEAR

*TIGHTEN TO 4.5 N.m (40 lbf in) TORQUE. LOOSEN NUT AND TIGHTEN SO THAT SHAFT TURNS WITH 0.56–0.90 N.m (5–8 lbf in) TORQUE. **TIGHTEN TO 2.3 N.m (20 lbf in) TORQUE.

11591

FIGURE 12. STEERING GENERATOR ASSEMBLY

CAUTION If the gears or the bearings are replaced, make sure to install the key, bearings and seals as shown in FIGURE 12. Make sure to fill the bearings and cavities with multi–purpose grease. Make sure to follow the torque notes in FIGURE 12.

CAUTION The electronic components can be damaged by electrostatic discharge. Use a special floor pad to help prevent an electrostatic charge. ALWAYS remove the electrostatic charge on your body before touching electronic components. Connect a static strap to your wrist and a good earth ground. Follow the directions on the package of the component.

ECM (See FIGURE 13.)

Replacing Complete Module 12

1. Disconnect the battery so that the connector is completely free. Open the electrical compartment door, discharge capacitor C1 and remove the ECM cover.

11033

1. TERMINAL STRIP 2. LOGIC BOARD 3. SCREWS

4. PLUGS (A–E) 5. PINS 6. EPROM 11026

FIGURE 13. ECM PARTS 2. To replace the complete module, install tags on the wires at the terminal strip for installation. Disconnect the wires from the terminal strip. Remove the electrical plugs from the edge of the logic board. Remove the capscrews that fasten the module to the plate on the door and remove the module. Install a thin coat of thermal compound on the heat sink of the replacement module before installing the module in the enclosure.

3. Install a thin coat of thermal compound on the enclosure on the side that touches the plate. Install the enclosure and the replacement module on the plate. Carefully install the electrical plugs and wires.

4. Adjust the ECM for the replacement sensor as described in the Test Procedures of WIRE GUIDANCE, DESCRIPTION, 2200 SRM 317.

5. Install the ECM cover. Close and fasten the electrical compartment door.

Replacing Logic Board NOTE: The logic board does not normally get damaged. The logic board can be damaged from a malfunction of the power board. If the power board has a fault, replace the complete module. If physical damage causes a fault in the logic board, replace the logic board as described in the following procedure.

CAUTION The electronic components can be damaged by electrostatic discharge. Use a special floor pad to help prevent an electrostatic charge. ALWAYS remove the electrostatic charge on your body before touching electronic components. Connect a static strap to your wrist and a good earth ground. Follow the directions on the package of the component.

1. Disconnect the battery so that the connector is completely free. Open the electrical compartment door, discharge capacitor C1 and remove the ECM cover.

2. Remove the electrical plugs from the edge of the logic board. Remove the screws that fasten the logic board. Carefully pull the logic board off the pins (P2) that connect the logic and power boards.

3. Make sure the replacement logic board is the correct part number and has the correct “EPROM”. Carefully install the replacement logic board on the pins (P2).

Make sure the pins are in alignment before pushing the board into the correct position. Install the screws to fasten the logic board.

4. Install the plugs on the edge of the logic board. Adjust the ECM as described in the Test Procedures.

5. Install the ECM cover, close and fasten the electrical compartment door.

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Replacing EPROM (See FIGURE 14.)

CAUTION The EPROM can be damaged by electrostatic discharge. NEVER remove the new EPROM from the original container until all preparations have been made. Always follow the instructions that come with the package. Do the following procedures carefully to prevent damage to the EPROM.

CAUTION Remove all large pieces of plastic, vinyl or styrofoam from the work area. Remove all plastic, vinyl or styrofoam from the immediate work area. This includes all plastic bags and styrofoam cups.

1. Disconnect the battery so that the connector is completely free. Open the electrical compartment door, discharge capacitor C1 and remove the ECM cover.

2. Install a ground wire between the ECM case and an earth ground. An earth ground can be a cold water pipe or other metal that makes a good electrical connection to the earth.

3. Connect a special static strap to your wrist and the ECM case.

11592

CAUTION NEVER touch the electrical connectors (legs) of the EPROM. Touch only the body of the EPROM. 4. Remove the replacement EPROM from the packing, but do NOT remove it from the holder.

5. Carefully lift the small lever at one end of the EPROM to remove it from the socket on the logic board. Hold the body and remove the EPROM from the ECM. Carefully install the EPROM in the holder from the replacement EPROM.

CAUTION Find the small index notch in the end of the EPROM. Make sure this notch is toward the test points on the logic board during installation.

6. Carefully remove the replacement EPROM from the holder and install it in the socket.

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STATIC STRAP EPROM BODY ELECTRICAL CONNECTORS (LEGS) HOLDER INDEX NOTCH LEVER SOCKET TEST POINTS

FIGURE 14. REPLACING EPROM

STEERING MOTOR AND SPEED REDUCER (See FIGURE 15.)

1. Make sure the MDU is in position for straight travel.

Open the electrical compartment doors.

2. Install tags on the electrical leads for the steering motor for correct connections to terminals A1 and A2 during installation. Disconnect the electrical leads from the steering motor terminals.

11029

1.

2.

3.

4.

CAPSCREWS STEERING MOTOR AND REDUCER STEERING CHAIN CHAIN SPROCKET 11030

1.

2.

3.

4.

MOTOR ADAPTER GASKET KEY REDUCER HOUSING

5.

6.

7.

8.

WORM GEAR SET BEARING CONE BEARING CUP LOAD RING

9.

10.

11.

12.

OIL SEAL OUTPUT SHAFT COVER SNAP RING

13.

14.

15.

16.

COVER RING SPACER BALL BEARING PLUG

FIGURE 15. STEERING MOTOR AND SPEED REDUCER 3. Remove the four capscrews and lockwashers that moving it away from the worm shaft. Rotate the worm fasten the speed reducer to the truck frame. Remove the shaft during removal. If the bearings will be replaced, chain from the sprocket and remove the steering motor carefully remove the cups from the cover and housing. and speed reducer.

Use a press to carefully press the bearings and gear off the shaft.

4. If necessary, remove the steering motor from the 7. Remove the snap ring from the end of the worm speed reducer. Disassemble the speed reducer as deshaft. Remove the motor adapter from the housing. Rescribed in steps 5 through 12. If the speed reducer will move the spacer. Use a soft metal drift to carefully renot be repaired, install the steering motor and speed remove the worm shaft from the housing. Remove the ducer as described in step 13. snap ring and use a press to remove the bearing from the end of the worm shaft.

5. Remove the sprocket from the output shaft of the speed reducer and drain the oil out of the speed reducer 8. Use a press to install the ball bearing on the end of housing. Pry the cover ring off the housing. Carefully the worm shaft. Install spacer and snap ring. Install the remove the snap ring. worm shaft and bearing in the housing. Install the other 6. Install tape over the key slot on the output shaft.

Carefully pry the cover off the housing and remove it from the shaft. Remove the output shaft assembly by

snap ring. Install the motor adapter.

9. Install a thin coat of Permatex #2 on the gasket and install the gasket. Lubricate the worm shaft extension 15

and lip of the oil seal with oil. Do not damage the lip of the oil seal during installation. Install the motor adapter.

5. Install the limit switch on the bracket using the two screws, washers and nuts. Adjust the limit switches as described in the Adjustment procedure.

10. Use a press to install the gear and bearings on the output shaft. Use the press to install the bearing cup into the housing. Install the shim, load ring, oil seal and bearing cup in the cover. Use grease to hold the parts in the cover.

11. Install the output shaft assembly in the housing. Rotate the worm shaft during installation. Use a press with a capacity of approximately 2635 kg (5800 lb) to install the cover assembly. Remove the cover. Remove the shim from the cover. Install the oil seal, load ring and bearing cup. Install a thin coat of LoctiteR 515 on the sealing surfaces and install the cover. Install the cover snap ring and cover ring.

12. Install the sprocket using the key and two snap rings. Install the motor on the motor housing.

CAUTION Do not install the 24V motor (Pacific Scientific BA 3724–4334–56C) on 36V lift trucks. High current peaks will damage the ECM power transistors.

13. Hold the speed reducer in the correct position and install the chain on the sprocket. Install the speed reducer and motor assembly on the lift truck Make sure the housing is filled to the level of the level plug (center). Fill at the top plug. Use the special lubricant shown in the lubrication table in the section PERIODIC MAINTENANCE, 8000 SRM 236.

LIMIT SWITCHES (See FIGURE 16.)

1. Disconnect the battery connector and open the electrical compartment doors.

2. Install tags on the wires for correct connection during installation. Remove the wires from the limit switch to be replaced.

11029

1.

2.

3.

4.

5.

6.

7.

MDU POTENTIOMETER BRACKET SCREWS FOR MDU POTENTIOMETER MDU GEAR POTENTIOMETER PINION STOP SCREW LIMIT SWITCHES

FIGURE 16. LIMIT SWITCHES AND STEERING POTENTIOMETER

STEERING POTENTIOMETER (See FIGURE 16.)

1. Disconnect the battery connector and open the electrical compartment doors.

2. Remove the ECM cover and remove plug A from the edge of the logic board.

3. Remove the three screws that fasten the steering potentiometer on the bracket. Remove the steering potentiometer and install the replacement potentiometer on the bracket.

4. Connect the plug of the steering potentiometer leads to the ECM logic board. Install the ECM cover.

5. Adjust the steering potentiometer as described in the Adjustment procedures.

3. Remove the two screws, nuts and washers that fasten the limit switches to the bracket. Remove the limit switch to be replaced.

SHUT–OFF BOARD (See FIGURE 17.)

4. Install the wires on the replacement limit switch according to the tags.

The electronic components can be damaged by electrostatic discharge. Use a special floor pad to help

16

CAUTION

prevent an electrostatic charge. ALWAYS remove the electrostatic charge on your body before touching electronic components. Connect a static strap to your wrist and a good earth ground. Follow the directions on the package of the component.

3. Carefully remove the four nuts that fasten the corners of the shut–off board. Do not let the spacer on each capscrew fall. Remove the shut–off board.

1. Disconnect the battery connector so that it is completely free. Open the electrical compartment door and discharge capacitor C1.

4. Install the replacement shut–off board. Install the capscrews with the spacers between the board and the door. Connect the wires as shown in FIGURE 17.

There are no adjustments.

2. Install tags on the wires of the shut–off board for correct connection during installation. Remove the wires fastened to the terminal strip of the shut–off board.

5. Close the electrical compartment door and connect the battery connector.

1

3 2 2 36 3

11031

1.

2.

3.

4.

4

ELECTRICAL PANEL SHUT–OFF CARD NUTS CARD TERMINAL STRIP

FIGURE 17. SHUT–OFF BOARD

17

TROUBLESHOOTING TROUBLE

POSSIBLE CAUSE

PROCEDURE OR ACTION

Truck will not steer or move.

Battery disconnected.

Shut–off has occurred.

Connect battery.

Set key to Off, Start and On.

No action when steering wheel is turned.

Circuit between steering generator and ECM is damaged.

Steering generator is damaged.

ECM has no output to steering motor.

Power leads between ECM and steering motor are damaged.

Steering motor or speed reducer is damaged.

MDU is against stop.

Check connections and wires 104 and 105.

Replace generator.

Check logic and power driver circuits.

Check connections and leads 122 and 123.

Replace steering motor or speed reducer.

Use large screwdriver in end of steering motor shaft to move MDU away from stop.

Steering is loose.

Steering chain is loose.

Connect lines properly. Remove air from the system.

Steering function continues after the steering wheel stops.

The steering control unit was assembled wrong or has damage.

Adjust chain.

Truck tries to turn in opposite direction. (LED 1 and LED 2 do not illuminate correctly)

Steering motor leads reversed.

Steering generator leads reversed.

MDU potentiometer leads reversed.

Correct motor leads.

Correct generator leads.

Correct potentiometer leads.

18

INTRODUCTION GENERAL This section describes the procedures for troubleshooting and repair of the EV–1 motor controller. The EV–1 motor controller is used, with modifications, in several series of lift trucks. There are many components that are not part of the motor controller, but give inputs to it.

These components include the following: (1) Key Switch, (2) Start Switch (some units), (3) Brake Switch, (4) Foot Switch, (5) Seat Switch (SitDrive units only), (6) Direction (FWD/REV) Switch, (7) Accelerator Potentiometer and (8) Guidance System (some units). You will also need the information in the following SRM sections for repair and troubleshooting:

tem repair section printed for the other series of lift trucks.

• EV–1 MOTOR CONTROLLER, DESCRIPTION, 2200 SRM 112. Has a description of the operation of the EV–1 controller. (This additional section is not normally necessary for troubleshooting as described in this section.)

This section is separated into the following parts:

• SRO and PMT Circuits. A short description of the SRO and PMT circuits and the sequence of operation of the controller is used as an introduction to Troubleshooting. You must understand some functions and operations so that you can select the correct fault procedure.

• ELECTRICAL SYSTEM, 2200 SRM 464. Describes the control switches and the adjustment of the control card that are special for the SitDrive lift trucks. There is a separate Electrical Sys-

• Troubleshooting. General procedures and fault analysis.

11

2 3 1

4

12 16

7

15

8 14 1.

2.

3.

4.

5.

6.

7.

8.

9.

6 13 TERMINAL STRIP ELECTRONIC DRIVES (PMT, 1A, FW) CONTACTOR FOR THE HYDRAULIC MOTOR CONTACTOR 1A SCR 1 ASSEMBLY POWER TERMINALS SCR 5 SCR 2 CARD TERMINAL STRIPS

7090

5

6 10 9 10. CONTROL CARD 11. CAPACITOR 1C 12. TRANSFORMER AND INDUCTOR ASSEMBLY 13. “REVERSE” CONTACTOR 14. “FORWARD” CONTACTOR 15. FIELD WEAKENING RESISTOR 16. FIELD WEAKENING CONTACTOR

FIGURE 1. EV–1 MOTOR CONTROLLER 1

• Checks and Repair. Additional information to make the checks and repairs of the faults you find in the troubleshooting procedures.

There are two contactors that are frequently found on the controller base: a contactor for the hydraulic pump motor, and a contactor for the power steering motor (if equipped). These two contactors are not part of the operation of the EV–1 controller. See the section on the

hydraulic system or the steering system for each series of lift trucks for more information.

WHEN YOU NEED HELP. Call a Hyster lift truck dealer if you have correctly followed a fault procedure and have not found the fault. This section describes the most common faults that occur in the EV–1 controller.

Hyster dealers have Service Engineers that can help you check and repair a fault that is not common.

SRO CIRCUIT AND PMT CIRCUIT STATIC RETURN TO OFF (SRO) CIRCUIT The “Static Return to OFF” (SRO) circuit is a safety circuit. The SRO circuit will prevent the operation of the lift truck if the operator is not in the correct position at the controls. The starting sequence is as follows: a. Close the seat switch (See NOTE). The operator must be in the correct position at the controls. The control card must receive the voltage from the seat switch before any of the other control signals to move the lift truck.

NOTE: SitDrive trucks have a seat switch. “R” and “N” trucks have a “brake switch” on the operator platform. StanDrive trucks have a platform switch. “E” trucks equipped with a seat brake do not use the seat switch. b. Close the key switch. The key switch supplies the battery voltage to the control circuits. (The E20–120B lift trucks also have a switch connected to the parking brake. The parking brake must be released before battery voltage is supplied to the control card.) c. Move the controls to operate the lift truck. The control card makes a comparison of the voltage signal from the direction switch at L9 or L10 with the voltage signal from the seat (foot) switch at L5 and L7. If the voltage signal to L9 or L10 comes before the voltage signal from the seat (foot) switch at L5 and L7, the lift truck will not operate.

2

See the sections ELECTRICAL REPAIRS AND ADJUSTMENTS for each series of lift trucks for more information on the control switches.

PULSE MONITOR TRIP (PMT) The PMT circuit opens the direction contactors if SCR 1 has two pulses without going to OFF between the pulses. The PMT circuit is part of the control card. After the SRO circuit is complete, the control card applies and senses the voltage across SCR 1. If the voltage across SCR 1 stays low, there is a fault across SCR 1. A fault across SCR 1 can be caused by a short–circuit in SCR 1 or the tips of contactor 1A welded closed. The voltage must be at least 50% of battery voltage before the control card will permit the direction contactor to close.

The control card checks the traction circuit for faults during operation of the lift truck. If the SCR 1 stays ON for greater than 32 milliseconds, the PMT signal opens the direction contactor. The control card will immediately close the direction contactor again. If the fault continues, the control card will immediately open the direction contactor again. The control card will not close the contactor again until the PMT circuit is reset by turning the key switch to OFF and then to ON gain.

This rapid double operation (double fault) of the direction contactor is an important indication when troubleshooting. This double fault normally indicates a fault in the OFF circuit for the SCR 1. The OFF circuit for the SCR 1 has the SCR 2, SCR 5, capacitor C1, and the transformer and inductor assembly.

Operator in the operator’s position (Seat switch on “E” and “J” trucks, “platform switch” on “N” and “R” trucks)

Control card energizes the PMT electronic driver and closes the FORWARD contactor

Control card sends gate signal to change SCR 1 and SCR 5 to ON Power pulse to traction circuit

Key switch to the ON position Controls set for FORWARD travel

Control card checks SRO circuit

Control card checks for approximately 50% battery voltage across SCR 1

Control card checks for 75% battery voltage across SCR 1

C1 fully charged with reverse voltage. SCR 5 goes OFF.

Control card sends gate signal to SCR 2

Control card sends gate signal to SCR 2

SCR 2 goes ON and connects capacitor C1 to the battery

SCR 2 goes ON and discharges C1 to cathode of SCR 1

Control card checks for a minimum of 75% of battery voltage across C1

SCR 1 goes OFF

SCR 2 goes OFF when C1 is charged

SCR 2 goes OFF Control card repeats cycle.

FIGURE 2. SEQUENCE OF OPERATION

THE SEQUENCE OF OPERATION

The following symbols are used in the description: R1 –– Right terminal strip numbers on the logic control cards

The sequence of operation shown in FIGURE 2. describes a sequence of the beginning condition and the SCR operation.

L1 –– Left terminal strip numbers on the logic control cards Wire 1 –– The wire number of the control circuits

TROUBLESHOOTING GENERAL PROCEDURES 1. Disconnect the battery and separate the connectors.

Check the specific gravity of the battery. If the specific gravity is less than 1.260, the battery is not fully charged or has a defect. A fully charged battery has a

specific gravity of 1.270 to 1.290. A discharged battery has a specific gravity of approximately 1.130.

You will need a Cir/Kit meter or an ohmmeter and voltmeter to make the following checks. The voltmeter must have a minimum rating of 20 000 ohms per volt.

3

2. Check for 50 000 ohms or more between each terminal of the battery connector for the lift truck and a clean connection on the frame. Remove any grounds between the controller and the frame of the lift truck.

controller. Make sure you also discharge the capacitor C1.

Carbon dust in a motor or other parts can cause a ground. Check if your customer has added some additional equipment that is causing a ground.

When the battery is connected, raise both drive wheels from the surface before making checks.

3. Check for voltage between each terminal of the connector fastened to the battery and a clean connection on the frame. It is normal to measure some voltage between the battery and the frame even if the resistance checks are correct. The leakage voltage is normally less than 30% of the battery voltage. A high leakage voltage can indicate a dirty battery or a battery with a defect.

Clean the battery and battery compartment as necessary.

4. Make a visual check for parts or wires that are loose, broken, or damaged.

The instructions for checking the parts and assemblies are described in the section Checks And Repair. The following WARNINGS and NOTES are given to help during troubleshooting:

WARNING Make sure you disconnect the battery and separate the connector before you disassemble any part of the

4

WARNING

NOTE: The correct meter polarity is necessary for the checks. The voltage checks are made between the indicated point in the troubleshooting chart and battery negative. Connect the meter negative to battery negative. The meter polarity for the resistance checks is indicated in the Repair And Adjustments section.

NOTE: Make an identification of any wires before you disconnect them. The wires must be connected again in the correct sequence.

Some checks and measurements must be made at the control card plug on the back of the control card. Tilt the control card from the controller so that you have access to the control card plug. Apply pressure with your fingers to loosen the locks that hold the plug in the control card. Twist a screwdriver blade in the slot where the control plug joins the control card and disconnect the control card plug. The pin arrangement is shown in FIGURE 6. The function of each pin of the control card plug is shown in FIGURE 7.

RAISE DRIVE WHEELS FAULT NUMBER 1. LIFT TRUCK WILL NOT MOVE IN EITHER DIRECTION. THE DIRECTION CONTACTORS NEVER CLOSE. Possible Causes:

• Short–circuit across SCR 1 • Short–circuit or open circuit in the control circuit • Accelerator circuit is damged or needs adjustment • Control card is damaged • Traction circuit has open circuit • 1A contacts welded closed • PMT electronic driver is damaged • Open fuse in control circuit or traction circuit

1.0

Check for a minimum of 50% of battery voltage across SCR 1.

1.2

Connect the battery and turn the key switch to the ON position. Close the seat switch and parking brake switch. Do not push on the accelerator pedal. Check for battery voltage between battery negative and L3 of the control card.

1.4

Battery voltage is at L3. Check for battery voltage at L5 and L7 on the control card.

1.6

Voltage at L5 and L7 is correct. Check for 8.2 volts between R1 of the control card and battery negative.

1.8

Voltage is correct at R1. Make sure the accelerator pedal is in the up position. Check for a battery voltage at L10.

1.10 No voltage at L10. Push the accelerator pedal down. Check for battery voltage at L10.

1.12 Voltage is correct at L10. Make sure the controls are set so that the lift truck will operate in the REVERSE direction. Check for greater than 0.5 volts between battery negative and R3 of the control card. Typical voltage is 1.0 to 2.0 volts.

1.1

Short–circuit in SCR 1. Disconnect the battery. Check that the 1A contacts are not welded together. Repair or replace a damaged contactor 1A. Repair damage in the traction circuit.

1.3

No Battery voltage at L3. There is a fault in the control circuit. Go to Fault 1.20

1.5

No voltage at L5 and L7. Check the seat switch or parking brake switch and the wires for an open circuit.

1.7

Voltage is outside the limits of 8.0 to 8.3 volts at R1. Replace the control card.

1.9

Battery voltage at L10. There is a fault in the accelerator circuit. Go to Fault 1.30.

1.11

No battery voltage at L10. There is a fault in the direction switch, or start switch, or the brake switch. Check the switches and wires for an open circuit. Go to Fault 1.30 to check the accelerator circuit.

1.13 A signal voltage of less than 0.5 volts normally indicates a fault in the traction circuit.

Go to Fault 1.40 To 1.14

5

From 1.12

1.14 Voltage at R3 is correct. Check for battery voltage between battery negative and the positive side of the REVERSE contactor coil.

1.16 Voltage is correct. Check for battery voltage between battery negative and the negative side of the REVERSE contactor coil.

1.18 Voltage is correct. Check for battery voltage at terminal 3 of the PMT electronic driver.

1.15 No battery voltage. Check the wires from the direction switch to the contactor coil for an open circuit.

1.17 No Battery voltage. Replace the contactor coil.

1.19 There is approximately battery voltage at terminal 3 of the PMT electronic driver. Replace the PMT electronic driver.

FAULT IN THE CONTROL CIRCUIT 1.20 No battery voltage at L3. Check for battery voltage between + cable 1P1 at the fuse panel and battery negative.

1.21 No voltage between cables. Check: • Battery plug • Power cables

1.22 Correct battery voltage between cables.

Check the fuse for the control circuit.

1.23 Replace a bad fuse. Check the following parts for a short–circuit: • Horn • Battery Meter • Hour meter • Power steering • Contactor coil • Key switch • Seat switch • Direction switch • Hydraulic pump switch • Brake switch

1.24 The fuse for the control circuit is good.

Check the key switch and wires for an open circuit. Check the seat switch and parking brake switch. There will be battery voltage at L3 at this step if the checks and repairs are correctly done.

6

FAULT IN THE ACCELERATOR CIRCUIT WITH AN ACCELERATOR CARD 1.30 Check the accelerator potentiometer voltage. Measure the voltage between R5 and battery negative. The correct voltage is 4.0 to 4.5 volts and decreases to 0.0 to 0.2 volts at maximum speed.

1.32 The accelerator potentiometer voltage is correct. Check the fuse to the accelerator card.

CAUTION A short–circuit between wire 15 and battery negative will damage the accelerator card before the fuse can protect the circuit.

1.34 Fuse is good. Connect the battery and close the key switch, seat switch, and parking brake switch. Set the controls to operate in the REVERSE direction and push the accelerator pedal. Check for approximately battery voltage between wire 15 and battery negative.

1.31 The voltage at R5 is wrong. Check the linkage and the adjustment of the accelerator potentiometer. If the voltage does not decrease smoothly between CREEP speed and maximum speed, replace the accelerator potentiometer.

1.33 Fuse is bad. Check the accelerator card for a short–circuit. Disconnect wire 15 from the accelerator card to the terminal strip. Connect the battery and close the key switch, seat switch, and push on the accelerator pedal. If the fuse opens again, replace the accelerator card.

1.35 No battery voltage on wire 15 to the direction switch. Replace the accelerator card.

1.36 Approximately battery voltage on wire 15 when the SRO circuit is correct. Raise the accelerator pedal to the UP position. If the voltage on wire 15 does not decrease to 0 volts, replace the accelerator card.

TRACTION CIRCUIT 1.40 Connect the battery and turn the key switch to the ON position. Measure the voltage between the anode and cathode of SCR 1.

The correct battery voltage is approximately 50% of the battery voltage.

1.41 No battery voltage across SCR 1. Disconnect the battery and discharge the capacitor C1. Check that the contacts of contactor 1A are not welded together. Repair or place contactor 1A.

1.42 Voltage across SCR 1 is correct. Replace the control card.

1.43 Check SCR 1 and D3 for a short–circuit.

Make resistance “quick check” between the heat sink of the anode and the cathode. See the Checks And Repairs section for more instructions to check the SCRs.

1.45 SCR 1 is bad. Check D3. A bad D3 can damage an SCR 1. Replace a bad SCR and a bad diode D3.

7

RAISE DRIVE WHEELS FAULT NUMBER 2.LIFT TRUCK WILL NOT MOVE IN EITHER DIRECTION. A DIRECTION CONTACTOR CLOSES AND THEN IMMEDIATELY OPENS [PMT FAULT].

Possible Causes:

2.0

2.2

2.4

8

• SCR 5 short–circuit or open circuit • SCR 2 open circuit or no gate signal • SCR 5 or SCR 2 suppressor is damaged • Capacitor C1 is damaged • Control card is damaged • Transformer and inductor assembly is bad

Connect the battery and turn the key switch to the ON position. Close the seat switch and parking brake switch. Set the controls to operate in the REVERSE direction.

Check the control card for 8.2 volts between R1 and battery negative. You can also make sure of a PMT fault by checking the signal voltage between R3 and battery negative.

Typical voltage is 1.0 to 2.0 volts. Less than 0.5 volts is a PMT signal.

The control card is correct. There is a PMT signal (less than 0.5 volts). Disconnect the battery and separate the connector. Discharge the capacitor C1. Make a resistance “quick check” of SCR 5. See the Checks And Repairs section for more instructions to check the SCRs. Disconnect the control card plug from the control card for access to the following pins: Pin Number 2 gate signal Pin Number 3 sensor wire (The sensor wire is electrically the same point as the cathode.)

SCR 5 is correct. Check SCR 2. See the Checks And Repairs section for instructions on checking the SCRs. The following pins of the card connector are for SCR 2: Pin Number 8 gate signal Pin Number 9 sensor wire (The sensor wire is electrically the same point as the cathode.)

2.1

No 8.2 volts at the control card. Replace the control card.

2.3

SCR 5 is bad. Replace the SCR5. Check D3 for an open circuit. An open D3 can damage SCR 5.

2.5

SCR 2 is bad. Replace SCR 2.

From 2.4

2.6

2.8

SCR 2 is good. Check C1 for a short–circuit.

Disconnect C1 and measure the resistance between the terminals. A good C1 will first indicate a low resistance and then increase to more than 100 000 ohms.

C1 is good. If the fault has not been found by this step, replace the control card. Connect the battery and check the operation of the lift truck.

NOTE: If a lift truck has a PMT fault that is not regular, check SCR 2. Replace an SCR 2 that indicates less than 50 000 ohms of resistance. An SCR 2 that indicates less than 50 000 ohms will sometimes cause a PMT fault in an operating circuit, but test good when checked by the tests described in Checks And Repairs.

2.7

C1 is bad. Replace C1.

2.9

The lift truck still has the fault. Disconnect the battery and discharge capacitor C1.

Check the inductor assembly. If the lift truck still has the fault, replace the SCR 2 suppressor. If replacement of the SCR 2 suppressor does not correct the fault, replace the SCR 5 suppressor. See Checks And Repairs for instructions.

NOTE: A suppressor for SCR 5 and SCR 2 often will not indicate a fault except during operation. If the other parts of the circuit are good at this step, replace a suppressor and check the operation of the lift truck.

NOTE: When the battery is connected and the key switch is ON, the capacitor will slowly charge to battery voltage in 4–5 minutes. If SCR 2 or SCR 5 has a short–circuit, C1 will charge immediately to battery voltage. If C1 has a short–circuit, it will not charge.

9

RAISE DRIVE WHEELS FAULT NUMBER 3. LIFT TRUCK WILL NOT MOVE IN EITHER DIRECTION. THE DIRECTION CONTACTORS CLOSE NORMALLY (NO PMT FAULT) Possible Causes:

• Open power fuse (short–circuit in traction circuit) • Accelerator potentiometer is damaged or linkage needs adjustment

• Open circuit power connections • Traction motor is damaged • SCR 2 has a short–circuit • Control card is damaged (no gate signal to SCR 1) • SCR 1 is damaged • Wires (YEL/GRN) to motor current sensor have an open circuit 3.0

Check the 500 ampere fuse to the traction circuit. Connect the battery and check for battery voltage between battery negative and the fuse.

3.2

Fuse for the traction circuit is good. Check the accelerator potentiometer voltage between R5 and battery negative. The correct voltage is 3.5 to 3.7 volts at CREEP speed and decreases to 0.0 to 0.2 volts at maximum speed.

3.4

3.1

Repair a damaged part.

The voltage at R5 is wrong. Check the linkage and the adjustment of the accelerator potentiometer. Repair as needed.

3.5

SCR 2 is damaged. Replace SCR 2.

3.7

No battery voltage between the anode and cathode of SCR 1. Disconnect the battery.

Check the following parts for an open circuit:

• Power cables and connections • Traction motor brushes

SCR 2 is correct. Connect the battery and turn the key switch to the ON position. Set the controls to operate in the FORWARD direction. The FORWARD contactor must close to do the following test. Check for battery voltage between the anode and cathode of SCR 1.

To 3.8

10

3.3

The accelerator potentiometer voltage is correct. Disconnect the battery and discharge C1. Check SCR 2 for a short–circuit.

NOTE: A short–circuit across SCR 2 or SCR 5 will also cause capacitor C1 to charge immediately to battery voltage when the key switch is turned to ON. If SCR 2 and SCR 5 are good, capacitor C1 will slowly charge to battery voltage in approximately 4–5 minutes.

3.6

Fuse for the traction circuit is open. Disconnect the battery. Check the following parts for a short–circuit: • Diode D3 • Power cables and connections to the traction motor.

Check the condition of the contacts in the direction contactors and the regenerative braking contactor to make sure they close correctly. Check the condition of the brushes and the commutator in the traction motor. Do necessary repairs.

From 3.6

3.8

There is battery voltage between the anode and the cathode of SCR 1. Disconnect the battery and use a tester to check SCR 1.

Make sure SCR 1 will go ON when a gate signal is applied.

3.10 SCR 1 is good. Check the wires to the motor current sensor for an open circuit. Make sure the black sensor wire between SCR 1 cathode and PC5 is connected correctly.

The traction circuit will not operate if the YEL/GRN wires between the current sensor and the control card are not connected to PC 13 and PC 14.

3.9

Replace a damaged SCR 1.

3.11

Repair a broken wire or a bad connection.

3.12 If the lift truck still has a fault at this step, replace the control card. Check that you are using the correct fault description. Check that you have correctly made the tests described in the troubleshooting steps. Call your Hyster Dealer for other recommendations.

FAULT NUMBER 4.LIFT TRUCK WILL MOVE IN ONLY ONE DIRECTION. DIRECTION CONTACTORS CLOSE NORMALLY (NO PMT FAULT).

Possible Causes:

4.0

• Bad direction contactor

Disconnect the battery. Check the condition of the contacts on the direction contactor.

Make sure that the contacts close correctly.

4.1

Repair a contactor that does not close correctly. Replace bad contacts.

11

RAISE DRIVE WHEELS FAULT NUMBER 5.ONE DIRECTION CONTACTOR WILL NOT CLOSE. THE TRACTION CIRCUIT OPERATES NORMALLY IN ONE DIRECTION. Possible Causes:

5.0

• Direction switch is damaged • Control card is damaged • Contactor coil is damaged • Broken or disconnected wires • PMT electronic driver is damaged on one output

Connect the battery and turn the key switch to the ON position. Close the seat switch, and push on the accelerator pedal. Set the controls to operate in the direction that the contactor will not close.

5.1

No voltage between L9 or L10 and battery negative. Repair or replace the directional switch or the wires. Make sure that you check for a broken wire that still has the outer insulation in good condition.

5.3

The PMT signal is less than 0.5 volts. The control card has a fault. Replace the control card.

5.5

No battery voltage on terminal (3 or 4) of the PMT electronic driver. Check for battery voltage at the negative terminal of the contactor coil. If there is 0.0 volts at the negative terminal, check the voltage on the positive terminal of the contactor coil. If there is voltage on the positive terminal, replace the contactor coil. If there is no voltage on the positive terminal, check and repair the direction switch or the wires.

5.7

Battery voltage across the PMT electronic driver indicates that the PMT electronic driver is not sending a signal to the contactor coil. Make sure that wire 13A is good between terminal 2 and battery negative. Disconnect the battery and replace the PMT electronic driver.

If the FORWARD contactor does not close, check for battery voltage between L9 and battery negative. If the REVERSE contactor does not close, check for battery voltage between L10 and battery negative.

5.2

Voltage at L9 or L10 is correct. Check the PMT signal. Check for approximately 1.0–2.0 volts between terminal 1 of the PMT electronic driver and battery negative.

5.4

The PMT signal from the control card is correct. Check for battery voltage on the terminal (3 or 4) of the PMT electronic driver for the contactor coil that will not close.

5.6

The voltage at terminal 3 or 4 of the PMT electronic driver is approximately battery voltage. Measure the voltage between terminal 3 (REVERSE) or terminal 4 (FORWARD) and terminal 2. Approximately 0.0 volts is correct between the terminal 3 or 4 and terminal 2.

12

RAISE DRIVE WHEELS FAULT NUMBER 6.DIRECTION CONTACTOR WILL NOT OPEN WHEN PEDAL IS RETURNED TO THE UP POSITION Possible Causes:

• Accelerator potentiometer is damaged or has a wrong adjustment

• Accelerator card is bad

6.0

6.2

Connect the battery and turn the key switch to the ON position. Close the seat switch and parking brake switch. Set the controls to operate in the REVERSE direction and push on the accelerator pedal. Measure the voltage between R5 and battery negative.

The correct voltage is 4.0–4.5 and decreases to 0.0–0.2 volts when the accelerator is moved to maximum speed.

The accelerator voltage decreases correctly. Check for a short–circuit in the accelerator card. A short–circuit in the accelerator will cause the following problems: The control card will sense a voltage from the direction switch at L9 or L10 and the contactor coil before the voltage is applied at L5 and L7. The SRO circuit will prevent the PMT electronic driver from closing the direction contactor. If the direction switch is moved when the SRO circuit is completed, the movement will momentarily interrupt the SRO circuit. The logic in the control card will sense the SRO circuit as being correct and the direction contactor will close. When the accelerator is returned to the up position, and the lift truck will stay at CREEP speed.

The direction contactor will not open.

6.1

The accelerator voltage is not correct. Repair or adjust the accelerator potentiometer.

6.3

The accelerator card has a short–circuit.

Replace the accelerator card.

CAUTION If an accelerator card has a short–circuit, check the coil of the contactor for a short– circuit. A short–circuit in the contactor coil will cause a fault in a replacement accelerator card. Make sure any fault has been corrected in the circuit for the direction contactor before you install a new accelerator card.

13

RAISE DRIVE WHEELS FAULT NUMBER 7. DIRECTION CONTACTORS CLOSE NORMALLY. THE LIFT TRUCK HAS ONLY LOW POWER OR MOVES SLOWLY. Possible Causes:

• Diode D3 has an open circuit • Thermal sensor has an open circuit • Accelerator potentiometer is damaged or needs adjustment • Control card has a fault • SCR 2 has a short–circuit • SCR 2 or SCR 5 suppressor is damaged • Field weakening contactor (if equipped) has the contacts welded closed • Auxiliary plugging contactor is open (E60–120B and N30–50C lift trucks only)

7.0

Disconnect the battery and discharge the capacitor C1. Check D3 for an open circuit.

7.2

D3 is good. Check SCR 2 for a short–circuit.

7.4

7.6

7.8

SCR 2 is good. Check the thermal sensor.

Disconnect the card plug and measure the resistance between the terminals. The correct resistance is approximately 120 to 150 ohms at 21°C (70°F).

Check the acceleration potentiometer.

Measure the voltage between R5 on the control card and battery negative. The correct voltage is 3.5 to 3.7 volts and decreases to 0.0 to 0.2 volts when the accelerator is moved to maximum speed.

If the lift truck is equipped with a field weakening contactor. check that the contacts are not welded closed. Check that the adjustments F.W.P.U. and F.W.D.O. on the control card are set to the correct specifications.

To 7 10

14

7.1

Replace a damaged D3.

7.3

SCR 2 is damaged. Replace SCR 2.

7.5

The thermal sensor is damaged. Replace the thermal sensor.

7.7

The accelerator voltage is not correct. Repair or adjust the accelerator potentiometer.

7.9

Repair a bad field weakening contactor.

From 7.9

7.10 Connect the battery and turn the key switch to the ON position. Close the seat switch and parking brake switch. If the lift truck is equipped with an auxiliary plugging contactor, check that the (AP) contactor closed after one of the direction contactors closed.

7.12 If the lift truck is equipped with a field weakening contactor, check if the contactor closed when you connected the battery and closed the SRO circuit.

7.11

The auxiliary plugging contactor did not close. See Fault Number 12 for the procedure to check the auxiliary plugging system.

7.13 If the field weakening contactor is closed, replace the field weakening electronic driver

7.14 If the fault is not found before this step, replace the control card.

NOTE: Make sure the correct replacement for the control card is used. If a 1H3 control card is used as a replacement for a 1E3 control card, the field weakening function can be continuously energized.

7.15 If a replacement control card did not correct the fault, replace the suppressor for SCR 2 and then SCR 5.

7.16 If the lift truck still has a fault at this step, check that you are using the correct fault description. Check that you have made the tests described in the troubleshooting steps. Call your Hyster lift truck dealer for other recommendations.

15

RAISE DRIVE WHEELS FAULT NUMBER 8.CONTACTOR 1A WILL NOT ENERGIZE. THE OTHER OPERATIONS OF THE LIFT TRUCK ARE NORMAL. Possible Causes:

• Control card is damaged or needs adjustment • Contactor 1A is damaged • 1A electronic driver is damaged • Accelerator potentiometer is damaged or needs adjustment • Accelerator card is bad • Violet sensor wire from T2 to pin 10 on the control card is open

8.0

Disconnect the battery and separate the connector. Check the adjustments on the control card.

8.2

Connect the battery and turn the key switch to the ON position. Set the controls so that the lift truck will normally operate. Check the adjustment of the accelerator potentiometer. Measure the voltage between R5 and battery negative. The correct voltage is 3.5 to 3.7 volts at CREEP and decreases smoothly to 0.0 to 0.2 volts when the accelerator is moved to maximum speed. The 1A contactor is normally energized at less than 0.5 volts.

8.4

The voltage at R5 decreases correctly.

Check the voltage at terminal 1 of the 1A electronic driver when the voltage at R5 has decreased to less than 0.5 volts.

NOTE: Check if the contactor 1A will close when the lift truck with a load is started on a ramp. If the contactor 1A will not close on a ramp, the accelerator potentiometer or the accelerator card is bad.

Check the output of the accelerator card.

Measure the voltage between R6 and battery negative. The correct voltage is approximately 8 volts at CREEP and decreases to 0.0 to 0.2 volts at maximum speed. This signal voltage must decrease to less than 0.5 volts before the control card will permit the contactor 1A to close on TIME. To 8.6

16

8.1

Set the adjustments according the specifications for the lift truck for which you are making repairs. The operation of the lift truck will not be correct if any of the sensor wires are disconnected or open.

8.3

The voltage at R5 is wrong. Check the linkage and the adjustment of the accelerator potentiometer. If the voltage does not decrease smoothly between CREEP and maximum speed, replace the accelerator potentiometer.

8.5

The signal voltage from the accelerator card does not decrease to less than 0.5 volts. Disconnect the battery and replace the accelerator card.

From 8.4

8.6

8.8

The voltage at R6 decreases correctly.

Check the voltage at R8 when the voltage at R6 has decreased to 0.0 to 0.2 volts.

1.0 to 2.0 volts at R8. Check for battery voltage between terminal 3 of the 1A electronic driver and battery negative.

8.10 No battery voltage across the electronic driver. Check for battery voltage at the positive side of the coil for the 1A contactor.

8.7

The voltage at R8 is less than 0.5 volts. The control card has a defect. Replace the control card.

8.9

There is battery voltage across the electronic driver. Disconnect the battery and replace the electronic driver.

8.11

Battery voltage at the positive side of the coil for the contactor 1A. Replace the coil.

17

RAISE DRIVE WHEELS FAULT NUMBER 9. THE FIELD WEAKENING CONTACTOR WILL NOT ENERGIZE (36–48 VOLT LIFT TRUCKS ONLY). THE OTHER OPERATIONS OF THE LIFT TRUCK ARE NORMAL. Possible Causes:

• Control card is damaged or needs adjustment • Accelerator potentiometer is bad or needs adjustment • Accelerator card is bad or needs adjustment • Field weakening contactor is damaged • Electronic driver for field weakening is damaged

9.0

Check adjustments C/L, F.W.P.U. and F.W.D.O. on the control card. Check the wires between the current sensor and the control card.

9.2

Turn the key switch to ON and set the controls so that the lift truck can operate normally. Check the adjustment of the accelerator potentiometer. Measure the voltage between R5 and battery negative. The correct voltage is 4.0 to 4.5 volts and decreases smoothly to 0.0 to 0.2 volts when the accelerator is moved for maximum speed.

9.4

9.6

9.8

The accelerator potentiometer is correct.

Check the output of the accelerator card.

Measure the voltage between R6 and battery negative. The correct voltage is approximately 8 volts at CREEP and decreases to 0.0–0.2 volts at maximum speed. This signal voltage must decrease to 0.5 volts before the control card will permit the field weakening contactor to close.

The signal voltage decreases correctly at R6. Measure the voltage between R9 and battery negative when the voltage at R6 is less than 1.0 volts.

The voltage is correct (typical voltage is 1.0 to 2.0 volts when R6 is 0.5 volts).

9.1

Set the adjustments according to the specifications for the lift truck for which you are making repairs. The operation of the lift truck will not be correct if any of the sensor wires are disconnected or open.

9.3

The voltage at R5 is wrong. Check the linkage and the adjustment of the accelerator potentiometer. If the voltage does not decrease smoothly between CREEP and maximum speeds, replace the accelerator potentiometer.

9.5

The signal voltage from the accelerator card does not decrease to 0.5 volts. Disconnect the battery and replace the accelerator card.

9.7

The voltage at R9 is less than 0.5 volts. Replace the control card.

9.9

There is battery voltage across the electronic driver, disconnect the battery and replace the electronic driver.

9.11

Battery voltage at the positive side of the coil for the field weakening contactor. Replace the coil.

Check for battery voltage between terminal 3 of the electronic driver for field weakening and battery negative.

9.10 No battery voltage across the electronic driver. Check for battery voltage at the positive side of the coil for the field weakening contactor.

18

FAULT NUMBER 10. PLUGGING PROBLEMS

10.0 Plugging is too quick.

10.1 Plugging is too slow.

Check the PLUG adjustment on the control card.

Check the PLUG adjustment on the control card.

Check D4 for an open circuit.

Replace the control card if there is no adjustment.

Check if the current sensor wires are broken or disconnected.

Replace the control card if there is no adjustment.

FAULT NUMBER 11. WHEN KEY SWITCH IS CLOSED, CONTACTOR 1A AND FIELD WEAKENING CONTACTOR (IF EQUIPPED) WILL CLOSE. DIRECTION CONTACTORS WILL NOT CLOSE. Possible Causes:

11.0

• Bad connection between control card and battery negative • Bad control card

Disconnect the battery and discharge capacitor C1. Check the wire that goes between pin 6 of the control card plug and the terminal for 13B. If the connections are good, make a resistance check to make sure that the wire is not broken.

11.1

Make a good connection or replace a broken wire. If the wire and connections are good, replace the control card.

19

FAULT NUMBER 12. PLUGGING PROBLEMS (E60–120B and N30–50C LIFT TRUCKS ONLY) NOTE: The weight of the E60–120 and N30–50C lift trucks can cause the brushes of the traction motor to wear quickly and also cause too much heat to be generated in the traction motor during plugging. These series of lift trucks have an auxiliary resistor for the current flow generated during plugging. When plugging, a plugging contactor opens so that the current flows through the plugging resistor. During lift truck operation, the auxiliary plugging contactor is closed except during plugging. This fault procedure checks the parts of the auxiliary plugging system.

12.0 Do the checks in 10.0 or 10.1 except do not replace the control card. Replace the control card if there is no plugging signal as described in the checks in this procedure.

12.2 Plugging is too quick. Measure the voltage between the terminal 2 of the auxiliary plugging card and battery negative during plugging. The correct voltage is approximately 8 volts. If there is no voltage from R10 to terminal 2 during plugging, replace the control card.

12.4 If the voltage is correct between R10 and terminal 2, check for battery voltage between terminal 5 of the auxiliary plugging card and battery negative during plugging.

If there is more than 0.5 volts at terminal 5, the auxiliary plugging card will not permit the auxiliary plugging contactor to open.

Replace the auxiliary plugging card. Check the auxiliary plugging contactor for a coil with a short–circuit.

12.6 Adjust the potentiometer adjustment on the auxiliary plugging card so that the auxiliary plugging contactor closes just after the lift truck comes to a stop.

20

12.1 Plugging is too slow. Disconnect the battery. Check that the auxiliary plugging resistor is connected correctly. Lift truck will not operate if the plugging resistor is open.

12.3 Replace the control card if there is no adjustment.

12.5 The coil for the auxiliary plugging contactor has a short–circuit. Repair the contactor coil.

1

6240

2

AUXILIARY PLUGGING CARD 1. ELECTRICAL TERMINALS 1 THROUGH 7 2. ADJUSTMENT POTENTIOMETER

TERMINAL NUMBER

FUNCTION

1 . . . . . . . . Battery negative.

2 . . . . . . . . Senses the plugging signal from R10 of the control card (0.0 volts when not plugging and increases to approximately 8.0 volts when plugging).

3 . . . . . . . . Battery negative. Connected to R4 on the control card.

4 . . . . . . . . Sends signal to R7 on the control card that plugging is completed.

5 . . . . . . . . Output voltage to energize the auxiliary plugging contactor. (Approximately battery voltage when contactor is closed. Less than 0.5 volts when the contactor is open during plugging.)

6 . . . . . . . . Battery positive supply.

7 . . . . . . . . Senses voltage at the armature terminal A1 to indicate when plugging is complete.

FIGURE 3. TERMINAL FUNCTIONS FOR THE AUXILIARY PLUGGING CARD

CHECKS AND REPAIRS GENERAL This section gives you additional information for making checks and repairs for faults found in the Troubleshooting section. Each series of lift trucks has its own arrangement of control switches and accelerator. To repair and adjust the control switches for lift trucks using the EV–1 motor controller, see the section ELECTRICAL SYSTEM, 2200 SRM 464 for the SitDriver units or the ELECTRICAL REPAIRS AND ADJUSTMENTS SRM section for the other series of electric lift trucks.

WARNING Some adjustments in this section must be done with the battery connected and power applied to the con-

troller. When making these adjustments, make sure the drive wheels are raised from the floor. Do not disable the SRO circuit.

WARNING Make sure you disconnect the battery and separate the connector before you disassemble any part of the controller. Make sure you also discharge the capacitors C1.

CHECKING FOR THE CORRECT OPERATION A service person must understand the operation of the lift truck with an EV–1 controller. If you understand and have operated a lift truck with normal operation, you will better understand a bad operation. Listen and 21

feel for a normal or bad operation as you operate the lift truck on a level surface.

1. Check the specific gravity of the battery. If the specific gravity is less than 1.260, the battery is not fully charged or has a defect.

2. Connect the battery connector. The horn can now be operated.

3. You must be on the operator’s seat to close the seat switch (or the operator’s platform to close the foot switch). Move the MONOTROL or accelerator to the operating range before you turn the key switch to the ON position. Turn the key switch to the ON position.

The SRO circuit will keep the logic from energizing the traction circuit. (A SitDrivesr with a FORWARD and REVERSE lever on a column mount can be checked the same as a lift truck with MONOTROL control.

Move the lever to a FORWARD or REVERSE position before moving the accelerator to the operating range). Release the accelerator to reset the SRO circuit.

Changing the controls from REVERSE to FORWARD or FORWARD to REVERSE will also reset the SRO circuit. The lift system can be operated when the key switch is ON. The lift truck is ready to move.

4. Slowly move the accelerator a small amount for the REVERSE direction. Listen for the reverse contactor to close. Listen for a very low volume hum from the controller. The lowest power that can be applied to the traction circuit when the direction contactor is closed is the CREEP speed. The CREEP speed can be adjusted so that the lift truck will or will not begin to move at the low power setting where the controller just begins to operate.

CONTROL AND POWER FUSES The power fuse panel is found under the floor plate or behind an access panel on the left side of SitDrive trucks. The power fuse panel is found in the motor compartment of other electric lift trucks. The control fuse is separate from the power fuse panel on all the lift trucks. The control fuse is under the floor plates of the SitDriver trucks. The fuses can be checked electrically with an ohmmeter.

CONTROL CARD The control card has an “Static Return to OFF” (SRO) circuit. The key switch and seat (or “brake switch” on the “N” and “R” trucks) switch must be closed before the accelerator is moved to operate the lift truck. A service person must understand the SRO sequence when troubleshooting. The SRO is a safety circuit. The switches for the SRO circuit are described in the section ELECTRICAL REPAIRS AND ADJUSTMENTS. A section is printed for each series of electric lift trucks.

2

1

9500

5. Move the accelerator a small amount so that the lift truck will begin to move very slowly.

6. Increased movement of the accelerator causes the lift truck to move faster. The SCR hum becomes louder with a higher frequency sound.

7. Check the plugging. During full speed in the reverse direction, move the control to the FORWARD full speed position. A correctly adjusted lift truck will stop smoothly and will then move in a forward direction. It will accelerate smoothly to full speed.

22

IC36450SC 24 48

OSCILLATOR ASM. IH3 VOLTS DC

DS 259A8100P1

1. LEFT TERMINAL STRIP 2. RIGHT TERMINAL STRIP

FIGURE 4. THE CONTROL CARD

STEP 1. Disconnect the Battery.

9530

STEP 2. Remove the (L) and (R) terminal strips.

Loosen the two mounting screws for each terminal strip only enough to release the terminal strip. If the screws are removed, the O–ring retainers can be lost.

STEP 4. Open the two latches. Push on the edge of the control card with your fingers. Rotate the control card towards you while lifting the control card from its pivots.

STEP 3. Use a screwdriver to remove each terminal strip from the control card. Leave the wires connected to the terminal strip.

STEP 5. Disconnect the control card plug from the control card.

23

The control card has a pulse monitor trip (PMT) circuit that checks for a short–circuit of SCR 1. If short–circuit occurs in a circuit connected to SCR 1, the logic in the control card will stop the lift truck.

CAUTION Some voltage measurements must be made with the SRO circuit complete. If you are working alone, put a weight in the seat to close the seat (or foot) switch.

You can operate the controls with your hand and also make the voltage measurement. Make sure the drive wheels are raised from the surface before doing troubleshooting.

CAUTION Do not try to put jumpers on the terminals in the controller. The terminals are close together and it is easy to make a very high cost error.

Removal The control card is a plastic case holding a printed circuit board with electronic parts. A 14 pin connector connects the logic control card to the traction circuit.

The control card has a left (L) and right (R) terminal strip. A reference number such as R5 in this section indicates terminal number 5 on the right (R) terminal strip.

There are two different control cards used in the electric lift trucks made by Hyster Company. Both control cards look the same. A label on the edge of the cases shows if the control card is a 1H3 or a 1E3. The 1E3 card has the Field Weakening function. In an emergency, a 1E3 card will work as a replacement for the 1H3 card. The Field Weakening function will not be energized. DO NOT use a 1H3 card as a replacement for a 1E3 card.

A bad control card cannot be repaired by service personnel and must be replaced. See FIGURE 4.

Installation To install a control card as follows: 1. Carefully install the control card plug.

2. Install the control card in the mounts and close the latches.

24

3. Install the terminal strips.

SCRs In this section on Checks And Repairs, there are instructions to check the SCRs. This part of the section describes the methods to check the SCRs.

An SCR “QUICK CHECK” Turn the key switch to the OFF position and disconnect the battery. Discharge the capacitor C1. Set the selector switch on your ohmmeter to the R x 100 scale.

Do not disconnect any wires. Make a resistance check between the anode and the cathode of the SCR. Replace any SCR that indicates a short–circuit.

The normal failure of an SCR is a short–circuit. This “quick check” will indicate a short–circuit in an SCR. This “quick check” can help you quickly find if the fault is in the traction circuit or one of the control circuits of an electric lift truck. This same check can be used to find a short–circuit in D3 or D4. This check will not always indicate a fault in D3 or D4. A diode failure in the traction circuit will first have a short–circuit. The increased current flow can cause the diode to open. To check an SCR or diode for an open circuit, complete the following procedures.

Checking An SCR NOTE: The following checks will indicate most SCRs with defects. The checks will not always indicate a fault that does not occur regularly during operation. Normally, an SCR with this type of fault will indicate a resistance between the anode and cathode of less than 50 000 ohms.

WARNING Make sure you disconnect the battery and separate the connector before you disassemble any part of the controller. Make sure you also discharge capacitor C1.

You will need a Cir/Kitr or an ohmmeter to check the SCRs. Disconnect the control card plug for access to the ends of the wires. See FIGURE 6. The SCRs can stay attached to the heat sink to make checks.

SEE FIGURE 7. FOR PIN FUNCTIONS 1.

2.

3.

4.

5.

5496

CATHODE THERMAL SENSOR ANODE GATE CATHODE SENSOR WIRE

FIGURE 6. CHECKING THE SCR

PIN NO.

FUNCTION

2. Measure the resistance between the gate wire and the cathode. Change the probe connections to the reverse direction and measure the resistance again. Replace the SCR if the resistance indicates zero or infinity on the R x 1 scale in either direction.

1 2 3 4 5

Not connected. Used for EV–1 Analyzer Signal to SCR 5 gate Senses SCR 5 cathode voltage Sends gate signal to SCR 1 Senses SCR 1 cathode voltage

6 7 8 9 10

Battery negative to control card Senses capactitor C1 voltage as output to control card Sends gate signal to SCR 2 Senses SCR 2 cathode voltage Senses traction motor voltage

11 12 13 14

Thermal sensor wire Thermal sensor wire Motor current sensor wire (current limit) Motor current sensor wire (current limit)

3. Measure the resistance between the cathode (1) and the cathode sensing lead (5). The resistance must be less than 5 ohms (R x 1 scale) or the SCR is bad.

FIGURE 7. PIN ARRANGEMENT AND FUNCTION FOR THE CONTROL CARD PLUG

4. Momentarily connect six volts from the Cir/Kitr [or a battery between the gate (+) and the cathode (–)]. The resistance indication on the Cir/Kitr or the ohmmeter will decrease to less than 10 ohms on the R x 1 Scale.

Replace the SCR if the resistance does not decrease when a six volt gate signal is applied momentarily.

Make sure you touch the gate wire momentarily with the six volt connection or you will damage the SCR. Make sure the polarity of your test circuit is correct.

1. Touch the probes of the Cir/Kitr or ohmmeter to the heat sink and the cathode wire. Measure the resistance.

Change the probe connections to the reverse direction and measure the resistance. Replace the SCR if the resistance indicates less than 50 000 ohms in either direction.

NOTE: Six volts is needed as a gate signal to check the SCRs. Use an ohmmeter and a six volt supply for a gate signal or use a Cir/Kitr meter to check the SCRs. The Cir/Kitr has a six volt supply.

25

5. When the checks are complete, connect the wires unless the SCR must be replaced.

The SCR 1 Assembly The SCR 1 assembly cannot be disassembled. The SCR 1 assembly includes an SCR 1 fastened between two metal blocks used as heat sinks. An epoxy case holds the complete assembly. There is a thin sheet of electrical insulation between the SCR 1 assembly and the base plate. The insulator permits heat to transfer from the heat sinks to the base plate.

To remove the SCR 1 from the circuit for making the checks, do the following: Disconnect the control card plug from the control card. Disconnect the power strap from the anode. Disconnect the wire for the gate signal.

Be careful that you do not let the wire connection screw fall into the controller.

NOTE: Silicon compound is used between the heat sinks and the parts of the controller. The purpose of this compound is to fill in the micrometer size spaces between the parts to give better heat flow. Always use a very thin layer of compound between the parts. Too much compound will be an insulator and cause both electrical and heat faults. It is better to use no compound instead of too much. There are two types of compounds:

6 1 5

D Part No. 304408 is a silicon bearing grease and is

used between the SCRs, diodes, and their heat sinks.

2

D Part No. 1198757 is a silicon compound and is

3

5907

4 1. CATHODE SENSOR CONNECTION 2. MOUNT HOLE FOR THERMAL SENSOR 3. CATHODE HEAT SINK

4. GATE TERMINAL 5. ANODE HEAT SINK 6. THERMAL SENSOR

FIGURE 8. SCR 1 ASSEMBLY

Thermal Sensor The thermal sensor is a resistor that changes resistance as the temperature increases. The thermal sensor is in a stud mount on the cathode heat sink for SCR 1. When the temperature increases above 85°C (185°F), the thermal sensor changes the input to the logic card. The card decreases the percent of SCR 1 ON time to decrease the SCR 1 temperature.

only used between heat sinks and the base plate.

This silicon compound must be used only as a very thin layer. DO NOT USE this silicon compound on SCRs and diodes.

Replacing The SCR 1 Assembly 1. Disconnect the electrical connections to the SCR 1 assembly.

2. Remove the two mounting screws.

3. Check the insulator between the SCR 1 assembly and the base plate. Replace the insulator if it has damage. The insulator is also a heat conductor. Use a very thin coat of silicon grease (Part No. 1198757 or approved equivalent) between the surfaces of the parts.

Keep dirt from the surfaces.

CAUTION The insulator is very thin. Dirt between the surfaces of the SCR 1 and the base plate will damage the insulator and cause a short–circuit.

Checking SCR 1

4. Install the new SCR 1 assembly. Make sure the heat sinks make full contact with the insulator and base plate. Check the resistance between both heat sinks and the base plate with an ohmmeter. A correct installation will indicate infinity.

See the section SCRs for doing the checks on SCR 1.

5. Install the electrical connections.

26

• Suppressors for SCR 2 and SCR 5

THE INDUCTOR AND CAPACITOR ASSEMBLY (THE “OFF” CIRCUIT FOR SCR 1)

• Capacitor C1

WARNING Make sure you disconnect the battery and separate the connector before you disassemble any part of the controller. Make sure you also discharge capacitor C1.

The transformer and inductor assembly is a plastic case that fastens to the base plate. This assembly is also the mount for the other parts.

The normal repair of the transformer and inductor assembly is to replace it. There are four screws that hold the inductor assembly to the base plate.

Checking The Transformer and Inductor Assembly

6026

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

T1 (TO SCR 1 CATHODE) T2 T4 INDUCTOR RESISTOR SCR 5 FILTER SCR 5 CATHODE WIRES SCR 2 1X SCR 2 FILTER T3 TRANSFORMER AND INDUCTOR ASSEMBLY

FIGURE 9. PULSE TRANSFORMER AND INDUCTOR ASSEMBLY There is an inductor and a capacitor assembly for the traction circuit. This assembly generates the reverse polarity voltage to change the SCR 1 to OFF for each pulse. This assembly has the following parts: • Transformer and inductor assembly • SCR 2 and heat sink • SCR 5 and heat sink

A fault in the transformer assembly does not often occur. Most faults that do occur at the transformer assembly are caused by loose internal connections. A transformer assembly will not normally indicate a fault except during the stress in an operating circuit. A check with an ohmmeter between T1 and T2 or between T3 and T4 will indicate an open circuit. A good transformer winding will indicate approximately zero ohms.

NOTE: The 72–80 volt lift trucks do not use a transformer winding between T1 and T2 because the inductance from the power cables is great enough to charge capacitor C1. There is a cable connection at T1, but T2 is removed on the 72–80 volt lift trucks.

Checking the Suppressors for the SCR 2 and SCR 5 The suppressors are a resistor and capacitor in series inside a plastic case. The suppressors prevent damage to the SCRs from electrical noise. To check the SCR suppressors, remove the suppressors from the transformer and inductor assembly. Touch the probes of an ohmmeter to the terminals. The indicator will begin to move toward the low resistance direction and then return to infinity. A bad suppressor can cause a fault that does not occur regularly during lift truck operation. A bad suppressor can also cause a fault similar to a bad SCR 2 or bad SCR 5.

NOTE: Checking these suppressors for a short–circuit can be difficult. Sometimes these suppressors will not indicate a defect except during the stress in an operating circuit.

The inductor resistor has a resistance of 4.75 to 5.25 ohms when checked with an ohmmeter.

27

Checking the SCR 2 and SCR 5 The heat sink and mount for the SCR 2 and SCR 5 are part of the pulse transformer and inductor assembly.

The heat sink is also the anode connection for the SCR. There are three wires connected to the SCR. A large black wire is the cathode wire. The white wire is the supply for the gate signal. The red wire is a sensor connection for the control card. The red wire is connected to the cathode wire at the junction of the SCR.

charge C1 and disconnect the terminals. Measure the resistance between the terminals. The ohmmeter will indicate a low resistance and increase to more than 100 000 ohms. A capacitor with a short–circuit must be replaced.

4

Replacing the SCR 2 and SCR 5 3

CAUTION Do not use a hammer and punch to loosen or tighten the SCRs. 2

NOTE: Make an identification of the wires before you disconnect them. The wires must be connected again in the correct positions.

NOTE: Silicon compound is used between the heat sinks and the parts of the controller. The purpose of this compound is to fill in the micrometer size spaces between the parts to give better heat flow. Always use a very thin layer of compound between the parts. Too much compound will be an insulator and cause both electrical and heat faults. It is better to use no compound instead of too much. There are two types of compounds: • Part No. 304408 is a silicon bearing grease and is used between the SCRs, diodes, and their heat sinks.

• Part No. 1198757 is a silicon compound and is only used between heat sinks and the base plate.

This silicon compound must be used only as a very thin layer. DO NOT USE this silicon compound on SCRs and diodes.

Disconnect the wires to the SCR. Use a deep socket to remove the SCRs. Put the wires through the top of the socket and use a handle or wrench to turn the socket.

Use a thin layer of silicon grease (Part No. 304408 or approved equivalent) between the surfaces of the heat sink and the replacement SCR. Tighten the SCR to a torque of 3.4 N.m (30 lbf ft).

Checking The Capacitor C1 The capacitor C1 is connected to the transformer and inductor assembly. To check C1 for a short–circuit, dis28

1.

2.

3.

4.

1 CAPACITOR NUTS MOUNTING BRACKET CAPSCREWS

9532

FIGURE 10. CAPACITOR C1

D3 And D4 Heat Sink Assembly The heat sink assembly for the diodes D3 and D4 is also the connection for the power cables. A suppressor for D3 and the motor current sensor is connected to this assembly. The heat sink assembly is connected to the base plate. A thin insulator with a silicone surface separates the heat sink assembly from the base plate.

Checking The Diodes D3 and D4 You will need a Cir/Kitr or an ohmmeter to check the rectifiers. Disconnect the cathode wires from the connectors. The diodes can stay attached to the heat sinks to make checks.

Touch the probes of the Cir/Kitr or ohmmeter to the heat sink and the cathode wire. Measure the resistance.

Change the probe connections to the reverse direction and measure the resistance. A good diode will indicate 7 to 14 ohms on the R x 1 Scale in one direction and greater than 50 000 ohms in the other direction.

tance. This small resistance between the two sensor wires sends a voltage signal to the control card. The voltage signal increases as the motor current increases.

The control card compares the voltage with the “C/L” current limit adjustment. The control card controls the current flow so that the traction circuit is not damaged.

5

4

2 9533

3 1.

2.

3.

4.

5.

7081

1

D3 D4 HEAT SINK MOTOR CURRENT SENSOR D3 SUPPRESSOR

FIGURE 11. THE D3 AND D4 HEAT SINK ASSEMBLY

2 1

1. SENSOR WIRES 2. POWER STRAP

FIGURE 12. MOTOR CURRENT SENSOR

Replacing The Diodes D3 and D4 THE ELECTRONIC DRIVER MODULE CAUTION Do not use a hammer and punch to loosen or tighten the diodes.

Disconnect the wire to the rectifier. Use a deep socket to remove the diodes. Put the wire through the top of the socket and use a handle or wrench to turn the socket. Use a thin layer of silicone grease (Part No. 304408) between the surfaces of the heat sink and replacement diode. Tighten the diode to a torque of 3.4 N.m (30 inch pounds).

NOTE: The D3 has a suppressor connected in parallel to the diode. The suppressor is a capacitor and resistor in series. This suppressor can be checked like the suppressors described on page 27.

MOTOR CURRENT SENSOR The motor current sensor is a shunt with two sensor wires connected. All of the traction motor current flows through this power strap. The metal between the connection points of the sensor wires has a small resis-

The electronic drivers are solid–state switches. The small voltage from the control card controls the operation of the electronic drivers. The electronic driver controls the operation of the contactors.

The electronic drivers are in a stack and connected to the base plate of the controller. The following list is the normal arrangement for the stack: • the PMT electronic driver is on the bottom next to the base plate.

• the electronic driver for field weakening (if used) will be in the middle.

• the electronic driver for 1A (if used) will be on top of the stack.

NOTE: The access to the electronic drivers on the bottom of the stack is difficult. Remove the two mounting screws and separate the drivers as necessary for access to the terminals. Make sure you disconnect the battery when you separate or connect the electronic drivers. Do not cause a short–circuit.

29

CONTACTORS

5913

Contactors are electromagnetic switches that close and open a power circuit. The largest contactor is normally used to control the hydraulic pump motor. Electric switches control the current to the coils for the contactors for the hydraulic pump motor and the power steering motor. A small electric current from the electronic drivers energizes the coils for the contactors that control travel and direction. The electromagnetic field in the coil moves the armature against spring pressure to close the contact. When the coil is deenergized, the spring pressure moves the armature and opens the contacts. When a spring holds the contacts of a switch open, the switch is said to be normally open (NO). If a spring holds the contacts of a switch closed, the switch is said to be normally closed (NC).

The direction contactors (FORWARD and REVERSE) each have two sets of NC and NO contacts.

When a coil for a direction contactor is energized, the NO contacts close and the NC contacts open. This design prevents the contacts from being closed in the wrong sequence.

9496

FIGURE 13. ELECTRONIC DRIVER MODULE

The electronic driver modules are most easily checked in the lift truck. Raise the drive wheels from the floor.

Connect the battery. Set the controls of the lift truck so that the electronic driver you are checking will operate.

Check that there is an input signal on terminal 1 of 1.0 to 2.0 volts.

If there is 1.0 to 2.0 volts at terminal 1 of the electronic driver, check for approximately battery voltage between battery negative and terminal 3 or terminal 4. If there is approximately battery voltage, the electronic driver has a defect. A good electronic driver will indicate a small voltage across the transistors during operation.

30

Lift trucks equipped with 1A and field weakening (FW) circuits have contactors with NO contacts. Lift trucks that have an auxiliary plugging resistor have an auxiliary plugging contactor with NO contacts. The hydraulic pump contactor also has NO contacts. Lift trucks equipped with power steering have a contactor in a closed case. A power steering contactor is replaced if it is bad.

“FORWARD” And “REVERSE” Contactors The FORWARD and REVERSE contactor assemblies control the direction of current flow through each traction motor. The traction circuit has a FORWARD and REVERSE contactor assembly. Each contactor assembly has the following parts: two sets of normally open (NO) contacts, two sets of normally closed (NC) contacts, and a coil. The coil is an electromagnet that moves the NO contacts to the closed position against spring pressure. The coil is in the control circuit. The contactor tips are in the traction circuit. A suppressor is part of each coil.

When a contactor coil is energized, the normally open (NO) contacts close and the normally closed (NC) contacts open. This action gives a direction control to the traction motor. The contacts normally have a long service life because the current flow through the contacts is

stopped before the contacts open. The SCR 1 is OFF before the contactor coil is deenergized. The only condition where the contacts open during a large current 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12 BASE PLATE 13.

COIL 14.

SUPPORT FRAME 15.

ARMATURE ASSEMBLY 16.

FIXED CONTACTS (NO) CENTER CONTACT CLAMP (2) FIXED CONTACTS (NC) UPPER CONTACT CLAMP WASHER (4) THROUGH BOLT (4) SPRING

flow is PMT.

CORE ASSEMBLY LOWER CONTACT SUPPORT MOVING CONTACT CARRIER (2) CONTACT SHIM MOVING CONTACT (NO)

17. SPRING CUP(2) 18. MOVING CONTACT SPRING 19. MOVING CONTACT (NC)

5497

NOTE: THE POWER CONNECTIONS FOR THE FIXED CONTACTS CAN BE DIFFERENT THAN SHOWN

FIGURE 14. FORWARD AND REVERSE CONTACTOR ASSEMBLY

CONTACTOR REPAIR (See FIGURE 14. and FIGURE 15.)

The normal repair to the contactor assembly is the replacement of the contacts, coil and the complete assembly.

Remove A Contactor Assembly Make an identification and disconnect the wires and cables from the contactor assembly. Remove the mounting screws and remove the contactor assembly.

The contactor contacts are made of special silver alloy.

The contacts will look black and rough from normal operation. This condition does not cause problems with the operation of the lift truck. Cleaning is not necessary. DO NOT USE A FILE ON THE CONTACTS. DO NOT LUBRICATE THE CONTACTS. When contact(s) need to be replaced, replace all of the contacts in a contactor at the same time. Replace the contacts every 1000 hours of operation or when the thickness of a contact is 30% less than that of a new contact. Replace contacts as described even if there is no transfer of metal.

Contactor Contacts Coil CAUTION ALWAYS replace all of the contacts of a contactor at the same time. Replace the Pump contactor contacts after 1000 hours of operation. Replace other contactor contacts when any area of a contact has worn 70% or more or there is any transfer of contact material.

Check the coil with an ohmmeter. The typical resistance for a coil is as follows: All 24V 36–48V Coil for Direction Contactor

5 to 9 ohms 23 to 29 ohms 31

1.

2.

3.

4.

5.

6.

7.

8.

9.

BASE PLATE COIL SUPPORT FRAME ARMATURE ASSEMBLY FIXED CONTACTS UPPER CONTACT CLAMP WASHER (4) THROUGH BOLT (4) SPRING

10 11.

12.

13.

14.

15.

16.

CORE ASSEMBLY LOWER CONTACT CLAMP MOVING CONTACT CARRIER CONTACT SHIM MOVING CONTACT MOVING CONTACT SPRING SPRING CUP

5498

NOTE: THE POWER CONNECTIONS FOR THE FIXED CONTACTS CAN BE DIFFERENT THAN SHOWN

FIGURE 15. PUMP, 1A OR FW CONTACTOR 36–48V Coils for 1A, FW and Auxiliary Plugging 36–48V Coil for Power Steering 72–80V Coils for Direction and 1A 72–80V Coils for Auxiliary Plugging

60 to 70 ohms 150 ohms 72 to 88 ohms 125 to 150 ohms

A suppressor diode (and sometimes a resistor in series) is part of the coil. The diode will cause the ohmmeter to indicate a difference in resistance in one direction. Reverse the probes of the ohmmeter to the opposite terminals and measure the resistance. Use the highest resistance indication. Replace the coil if it has damage.

Make sure the coil wires are connected again to the correct terminals.

If the coil in the contactor has an external suppressor, remove the suppressor and check the coil and the suppressor separately with an ohmmeter. The suppressor will have a high resistance in one direction and a low resistance in the other direction. Replace the suppres32

sor if the measurements are not as described. Make sure the coil wires are connected again to the correct terminals and install the suppressor on the coil.

CHECK THE PMT CIRCUIT The pulse monitor trip (PMT) circuit can be checked for correct operation. Use the following procedure to check the PMT circuit in the lift truck.

WARNING Incorrect operation of the PMT circuit will allow the SCR 1 to go fully “ON” without opening any contactors. The traction motor will run at high speed until the battery plug is disconnected.

1. Raise the drive wheels off the ground so that the lift truck will not move. Release the park brake.

2. Disconnect the battery.

3. Disconnect the gate lead from SCR 5 (white/purple wire). The gate lead has a push–on connector. Make sure end of lead does not touch any other surface.

4. Connect the battery.

5. Sit in the seat and turn the key to ON. Actuate the directional control (Monotrol pedal or column mounted lever) to forward or reverse.

6. Listen for a the direction contactor to open. The traction system will not operate. The traction motor controller will allow two power pulses before opening the contactor.

TERMINAL NUMBER

7. As soon as the PMT circuit disables the traction control turn the key switch to OFF. 8. Disconnect the battery.

9. Connect the SCR 5 gate lead.

10. Connect the battery and check for normal operation of the traction circuit.

FUNCTION

L1 . . . . . . . Not used.

L2 . . . . . . . Not used.

L3 . . . . . . . Battery positive to the control card. This voltage also resets the SRO check and the PMT circuit.

L4 . . . . . . . Not used when lift truck has MONOTROL pedal. On lift trucks with a direction control lever, this terminal is connected to L7. This connection is so that the SRO check does not deenergize the controller when the direction switch is in the NEUTRAL position.

L5 . . . . . . . Input for the SRO check. A four volts or greater signal must be received at this terminal before a voltage signal is applied at L9 or L10.

L6 . . . . . . . Not used.

L7 . . . . . . . Input for the SRO check. The controller is deenergized if battery voltage is removed from this terminal for more than 0.75 seconds after voltage is applied at L9 or L10.

L8 . . . . . . . Not used.

L9 . . . . . . . Battery voltage from the direction switch for the FORWARD direction.

L10 . . . . . . Battery voltage from the direction switch for the REVERSE direction.

R1 . . . . . . Test point for 8.2 volt power supply.

R2 . . . . . . Not used.

R3 . . . . . . Supplies 1.0 to 2.0 volt control signal to PMT electronic driver. Less than 0.5 volts is a PMT signal.

R4 . . . . . . Not used. Electrically the same as battery negative.

R5 . . . . . . The control card supplies 4.8 to 5.0 volts at R5. The accelerator potentiometer decreases this voltage by decreasing the resistance between R5 and battery negative. This voltage controls the ON time of the SCR 1 and controls the travel speed of the lift truck. When the voltage has decreased to less than 0.5 volts, the control card permits the contactor 1A to close.

R6 . . . . . . For lift trucks with a contactor 1A: Input signal to the control card from the accelerator card to begin 1A TIME. The time begins when the voltage signal decreases from 8.0 volts to 0.5 volts.

R7 . . . . . . Not used.

R8 . . . . . . 1.0 to 2.0 volt signal from the control card to the 1A electronic driver. The voltage signal causes the contactor 1A to close.

R9 . . . . . . 1.0 to 2.0 volt signal from the control card to the Field Weakening electronic driver for SitDrive trucks. The voltage signal causes the Field Weakening contactor to close. “R” trucksr and “N” trucks use this signal for a “soft” start.

R10 . . . . . E60–120B and N30–50C lift trucks only: supplies approximately 8.0 volts to the Auxiliary Plugging Card during plugging.

FIGURE 16. DESCRIPTION OF CONTROL CARD TERMINALS 33

CHECKS AND ADJUSTMENTS GENERAL This section has the checks and adjustment procedures for some of the electrical parts on the R30CH. To check and replace the EV-1 card and other parts, see the Checks and Repairs section of the EV-l TROUBLESHOOTING AND REPAIR (2200 SRM 155). To check, adjust or replace the accelerator card, see the ACCELERATOR CARD (2200 SRM 55).

See the ELECTRIC POWER STEERING (1600 SRM 220) for the description, adjustment or repair of the electrical parts of the steering system. The battery indicator is replaced and adjusted using the procedures in the BATTERY INDICATORS (2260 SRM 138).

Use a meter with a 20 000 ohms per volt rating or better to make measurements. Most digital voltmeters are good.

Accelerator Potentiometer (See Figure 1) A. Open the electrical compartment doors, disconnect the battery connector so that it is completely free and discharge capacitor C l.

B. Remove the capscrews that fasten the right hand side of the instrument panel. Open the instrument panel.

CHECKS CAUTION Proper meter polarity is necessary for some checks. Meter correct positive is indicated by + .

Meter correct negative is indicated by - .

C. Use an ohmmeter to check the resistance between wires 70 and 29 and between 71 and 29. Connect the ohmmeter to these wires on the terminal strip.

D. The two readings of Step C must be equal. Use the R x 100 setting and check for a smooth change in the resistance.

Move the direction and speed controller through the complete range. If the readings of Step C are equal and the resistance is smooth, the

FIGURE 1. ACCELERATOR POTENTIOMETER ASSEMBLY

accelerator potentiometer is good and correctly adjusted.

E. If the readings of Step C are not equal, adjust the accelerator potentiometer. Use the adjustment procedure in the Adjustments part of this section. If the change in resistance is not smooth, replace and adjust the accelerator potentiometer.

foot) distance. The 2.5 m (8.5 foot) distance at each end is for acceleration and a distance to stop the truck.

D. Have other personnel at each of the 10 m (33 foot) marks.

Operate the truck at full speed and check the total time it takes for the truck to travel the 10 m (33 foot) distance. The truck MUST travel at full speed for the total time of the 10 m (33 foot) distance.

Main Hoist Potentiometer A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C 1.

B. Remove the wires connected to the LEDEX terminals 5, 8 and 16. Use an ohmmeter set on the R x 100 setting. Check the resistance between wires 19 and 58 and between wires 48 and 58. The two resistance readings must be equal. The readings will be approximately 5K to 7.2K ohms.

C. If the two resistance readings in Step B are not equal, the main hoist potentiometer must be adjusted. See the Adjustment part of this section.

D. After the main hoist potentiometer is correctly adjusted, make sure to connect the wires to the LEDEX card. Connect wire 58 to terminal 5, wire 19 to terminal 8 and wire 13 to terminal 16.

WARNING Make sure all wires are correctly connected to the LEDEX card. The lifting and lowering operations can be different than the expected operation if the wires are not correctly connected.

Make sure no other person is in the area around the operator’s platform when the battery is first connected.

2.25 Speed Reduction Potentiometer A. Make sure the battery has a corrected specific gravity of at least 1.250.

B. Find a section of floor that is smooth and level for approximately 15 m (50 feet).

C. Make sure the operator’s platform is above 9 14 mm (36 inches). Move the truck to the end of the 15 m (50 foot) distance. Put marks on the floor for a 10 m (33 foot) distance in the center of the 15 m (50

E. If the time is less than 10 seconds, the 2.25 speed reducing potentiometer must be adjusted cw. If the time is more than 10 seconds, the potentiometer, must be adjusted ccw. Adjust the potentiometer using the adjustment procedure in the Adjustment part of this section.

1.5 Speed Reduction Potentiometer Some units that have high uprights have an additional switch and potentiometer to decrease the maximum travel speed an additional amount. This potentiometer decreases the maximum travel speed to 2.4 km/h (1.5 MPH). To check or adjust this potentiometer, the limit switch must be actuated or the circuit energized using another method.

A. Make sure the battery has a corrected specific gravity of at least 1.260.

B. Find a section of floor that is smooth and level for approximately 9 m (30 feet).

C. Make sure the operator’s platform is above the height where the speed is decreased to 2.4 km/ h (1.5 MPH). Move the truck to the end of the 9 m (30 foot) distance. Put marks on the floor for a 6.7 m (22 foot) distance in the center of the 9 m (30 foot) distance. The approximate 1 m (4 foot) distance at each end is for acceleration and a distance to stop the truck.

WARNING Do not make any sharp turns with the operator’s platform raised. The lift truck is less stable and the traction system is ~ deenergized and the brake applied if the steering is more than 5° of straight.

Do not use the brake to stop. Stop the truck gradually using the speed controller.

D. Have other personnel at each of the 6.7 m (22

foot) marks. Operate the truck at full speed and check the total time it takes for the truck to travel the 6.7 m (22 foot) distance. The truck MUST travel at full speed for the total time of the 6.7 m (22 foot) distance.

E. If the time is less than 10 seconds, the 1.5 speed reduction potentiometer must be adjusted cw. If the time is more than 10 seconds, the potentiometer must be adjusted ccw. Adjust the potentiometer using the adjustment procedure in the Adjustments part of this section.

ADJUSTMENTS NOTE To adjust the accelerator card, see the ACCELERATOR CARD (2200 SRM 55). To adjust the battery indicators, see the BATTERY INDICATORS (2260 SRM 138.)

Adjustment can be necessary after replacing a part or after a malfunction occurs. None of the potentiometers normally need periodic adjustment. Some of the potentiometers are sealed after factory adjustment and can be adjusted only after replacement. Adjustments can also be necessary for different performance needs. The card adjustment potentiometers have clockwise and counterclockwise stops. They may be set by the number marks and the screwdriver slot position. See Figure 2. To find which end of the screwdriver slot to set to the number, note the slot position. Turn the adjustment screw to the counterclockwise stop. The

end of the slot that is at the number 1 is the end of the slot to set to the number. The potentiometers on a new card need to be set to the numbers shown in Figure 2. These units are not equipped with 1A or field weakening, so these adjustment numbers are not given. The battery must be charged to a specific gravity of 1.260 or higher before adjustments are made.

Adjusting Creep Speed The creep speed adjustment sets the minimum unit speed. A very slow speed is good for most operations. The adjustment range does allow setting the speed for special operations. Normal adjustment will allow the unit to just move as the direction contactors just energize. The setting shown in Figure 2 will provide a smooth, slow creep speed at approximately 30.40 cm/min. (one foot per minute). Setting the potentiometer to either OFF or 9 can result in rough or too fast operation.

Adjusting Controlled Acceleration This adjustment sets the maximum acceleration rate for SCR 1 pulses. This prevents the pulse rate from increasing too fast when the operator sets the speed controller to maximum. Too high a setting will cause the traction motor brushes to wear too fast. Too low a setting will cause the unit to accelerate too slowly. The potentiometer can be set for a special operation. Setting the adjustment to the right will cause the unit to accelerate faster. Setting a new card as shown in Figure 2 will result in normal acceleration.

FIGURE 2. CARD ADJUSTMENT

Adjusting Current Limit This adjustment sets the point where the current control will override the pulse circuit. This prevents the traction motor current from getting too high in normal SCR operation. The adjustment is set at the factory and will not require adjustment. Set a new card as shown in Figure 2.

Adjusting Plugging The plugging adjustment sets the amount of reverse torque that is applied by the traction motor. The correct setting for this adjustment will allow the unit to come to a smooth stop.

The unit must stop within the following distances: A. 1.8 to 2.4 meters or 6 to 8 feet with no load.

B. 3.4 to 4.0 meters or 11 to 1 3 feet with a rated load. The setting can be changed for a special operation. A setting of 1 will result in a long stopping distance. A setting of 9 will result in too strong a plugging torque. Set a new card as shown in Figure 2 for normal plugging.

Accelerator Potentiometer (See Figure 1) A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

B. Connect an ohmmeter as described in Checks for the accelerator potentiometer.

C. Loosen the nut on the crank. Adjust the potentiometer shaft so that the reading between wires 70 and 29 equal the reading between wires 71 and 29. As one reading increases, the other reading decreases.

D. Tighten the crank nut. Move the controller in both directions and check that the readings are still equal. The readings must be equal when the controller is in the Neutral position.

Main Hoist Potentiometer Adjustment A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

B. Remove the capscrews that fasten the left hand instrument panel. Open the panel. Remove the potentiometer wires 19, 48, and 58 connected to the terminal strip. Use an ohmmeter to check the resistance between wires 19 and 58 and between wires 48 and 58.

C. Remove the covers over the main hoist control. Loosen the set screw in the coupling on the potentiometer shaft. Adjust the shaft so that the resistance readings of Step B are equal.

Tighten the setscrew without moving the potentiometer shaft.

Install the covers.

WARNING Make sure all wires are correctly connected to the LEDEX card. The lifting and lowering operations can be different than the expected operation if the wires are not correctly connected. Make sure no other person is in the area around the operator’s platform when the battery is first connected.

D. Connect the potentiometer wires to the terminal strip. Close the instrument panel and install the capscrews. Close the electrical compartment doors and install the capscrews.

Ledex Card Adjustment (See Figure 3) A. Open the electrical compartment doors and put some thin cardboard or heavy paper between the contacts of the main pump AND auxiliary contactors. Make sure the battery is connected.

B. Make sure the main hoist potentiometer is correctly adjusted. Make sure the main hoist control is in the NEUTRAL position. Use two digital voltmeters and connect both voltmeters - to terminal 11. Connect one voltmeter + to terminal 10. Connect the other voltmeter + to terminal 13, Adjust the centering potentiometer (P3) for equal voltage readings on the voltmeters.

C. Have another person move the main hoist control lever in the LIFT direction. The knob must move to approximately 5° or 9.5 mm (3/8 or 0.38 inch) from the NEUTRAL position. Hold the lever in this position. Adjust the main pump potentiometer (P2) so that the pump contactor is just energized.

WARNING Make sure all wires are correctly connected to the LEDEX card. The lifting and lowering operations can be different than the expected operation if the wires are not correctly connected. Make sure no other person is in the area around the operator’s platform when the battery is first connected.

F. Remove the cardboard or heavy paper from both contactors so that both pump motors can operate. Make sure there is clearance above the upright so that the operator’s platform and upright can raise.

G. Have the person move the main hoist control lever smoothly from NEUTRAL to the LIFT stop. Adjust the auxiliary potentiometer (P4) for a smooth change from slow to fast speed LIFT. Attachment Switch Adjustment (See Figure 4)

FIGURE 3. LEDEX ADJUSTMENTS

D. Have the person move the lever in the LIFT direction so that the knob is approximately 13 mm (1/2 or 0.5 inch) from the stop. Hold the lever in this position. Adjust the auxiliary pump potentiometer (P4) so that the auxiliary pump contactor is just energized. Have the person release the lever.

A. Open the electrical compartment doors and put a piece of thin cardboard or heavy paper in the contacts of the auxiliary pump contactor.

B. Remove the capscrews that fasten the panels over the hydraulic control valve. Remove the panels.

NOTE The sensitivity adjustment in Step E can be adjusted between approximately 4.5 to 11 volts. A setting near the low voltage increases the sensitivity of the hoist lever. Less lever movement has more operator’s platform movement. A setting near the higher voltage will give the lever less sensitivity.

E. Have the person slowly operate the main hoist control lever from the NEUTRAL postion to the LIFT position. Adjust the sensitivity potentiometer (Pl) so that the valve operates soon after the pump contactor is energized. Do this step several times for the best adjustment. Have the person release the lever.

FIGURE 4. ATTACHMENT SWITCH

NOTE The attachment switch does not operate when the attachment FREE LIFT control lever is pushed in the LOWER direction.

C. The attachment switch must energize the auxiliary pump contactor as soon as the control levers are moved.

D. If the switch does not energize the contactor as described in Step C, loosen the jam nuts on the switch. Adjust the jam nuts and switch so that the switch operates as described in Step C. Tighten the jam nuts.

E. Install the panels over the control valve, remove the cardboard or heavy paper from the contactor and close the electrical compartment doors.

FIGURE 5. SPEED POTENTIOMETERS

Speed Reduction Potentiometers (See Figure 5) To adjust the 2.25 or 1.5 speed potentiometers the speed must be checked after each adjustment. Open the right side of the instrument panel for access to the potentiometer. Make a minor adjustment to the specific potentiometer, then check the speed as

described in the Checks of this section. Repeat the adjustment and check for each potentiometer until the specific speed is correct. Adjustment of each potentiometer in the cw direction will increase truck speed. Put a silicon sealer on each potentiometer after the adjustment is correct.

REPAIR CAUTION Never use steam to clean any of the electrical parts.

WARNING Always disconnect the battery so that the connector is completely free before making any repairs to the electrical system. If not completely free, the connector can reconnect the battery during the procedure.

NOTE Replacement of the parts on the EV-1 traction control panels is in the Checks and Repairs section of the EV-1 TROUBLESHOOTING AND REPAIR (2200 SRM 155.)

NOTE Replacement of the electrical parts of the steering system is in the Repairs section of the ELECTRIC POWER STEERING (1600 SRM 220).

REPLACING THE ACCELERATOR CARD A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

B. The accelerator card is below the LEDEX card. Remove the wires for the accelerator card from the terminal strip.

NOTE The capscrews, nuts and washers that fasten the accelerator card and power disconnect module also fasten the shut-off card. This card is on the back of the electrical panel. Do not lose any of the capscrews, nuts or washers. Do not let the shutoff card fall.

C. Remove the capscrews, screw, washers and nuts that fasten the accelerator card and power disconnect module. Do not lose any of the parts. Do not let the shut-off card fall at the back of the panel. Remove the accelerator card.

D. Install the replacement accelerator card and power disconnect module. Install the nuts, washers and spacers in the correct order as removed.

pad. Remove the pad and potentiometer from the holder.

F. Install the replacement potentiometer and pad in the holder.

Install the holder and tighten the screws. Connect the potentiometer wires to the correct terminals on the terminal strip.

See the DIAGRAMS (RACKLOADER II) (8000 SRM 238) for the correct connections.

G. Install the crank on the potentiometer shaft. Adjust the accelerator potentiometer using the procedure in Adjustments of this section.

H. Close and fasten the electrical compartment doors and the instrument panel.

REPLACING THE MAIN HOIST CONTROL

E. Connect the wires for the accelerator card to the correct terminals. If necessary, see the DIAGRAMS (RACKLOADER II) (8000 SRM 238) for the correct connection.

A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

F. Adjust the accelerator card using the procedure in the ACCELERATOR CARD (2200 SRM 55). Close and fasten the electrical compartment doors.

B. Remove the capscrews that fasten the covers over the hydraulic control valve. Remove the covers.

REPLACING THE ACCELERATOR POTENTIOMETER (See Figure 1)

A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C 1.

B. Remove the capscrews that fasten the right side of the instrument panel and open the panel.

C. Remove the potentiometer wires from the terminal strip.

D. Loosen the nut on the crank and remove the crank from the potentiometer shaft.

E. Remove the two screws and washers that fasten the holder.

Remove the holder, potentiometer and

C. Remove the screws that fasten the control to the bracket.

Do not lose these metric screws. Remove the control.

D. Loosen the setscrew of the coupling on the shaft of the potentiometer. Loosen the nut on the potentiometer. Use a small soldering iron to carefully disconnect the wire leads from the potentiometer and remove the potentiometer. Too much heat at the circuit board can cause damage.

E. Use an ohmmeter to check the resistance between each end lead terminal and the center terminal. Adjust the potentiometer shaft so that the resistances are equal.

F. Carefully put the potentiometer in the correct position on the circuit board. Do not move the potentiometer shaft. Make sure the potentiometer washer and nut are on the shaft and the shaft is in the coupling. Tighten the nut without moving the shaft or potentiometer. Use the soldering iron to connect

the leads between the potentiometer terminals and the circuit board. Tighten the coupling setscrew.

REPLACING THE ATTACHMENT SWITCH (See Figure 4)

G. Install the main hoist control on the bracket.

A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

WARNING Make sure all wires are correctly connected to the LEDEX card. The lifting and lowering operations can be different than the expected operation if the wires are not correctly connected.

Make sure no other person is in the area around the operator’s platform when the battery is first connected.

H. Close and fasten the electrical compartment doors and install the panels over the hydraulic control valve.

REPLACING THE LEDEX CARD A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C1.

B. Disconnect the wires from the terminal strips on the LEDEX card.

C. Remove the four screws that fasten the LEDEX card and remove the card.

WARNING Make sure all wires are correctly connected to the LEDEX card. The lifting and lowering operations can be different than the expected operation if the wires are not correctly connected.

Make sure no other person is in the area around the operator’s platform when the battery is first connected.

D. Install the replacement LEDEX card and connect the wires to the correct terminals on the terminal strips. See the DIAGRAMS (RACKLOADER II) (8000 SRM 238) for the correct connections.

E. Adjust the LEDEX card using the procedure in the Adjustments of this section.

F. Close and fasten the electrical compartment doors.

B. Remove the capscrews that fasten the panels over the hydraulic control valve. Remove the panels.

C. Disconnect the wires to the attachment switch. Loosen the jam nuts and remove the switch from the linkage.

D. Install the replacement switch. Connect the switch wires to the same points.

E. Adjust the attachment switch using the procedure in the Adjustments of this section.

F. Install the panels over the hydraulic control valve and close and fasten the electrical compartment doors.

REPLACING THE SPEED REDUCTION POTENTIOMETERS (See Figure 5) A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C l.

B. Remover the capscrews that fasten the right side of the instrument panel. Open the panel.

C. Disconnect the wires for the speed reduction potentiometer being replaced. Remove the nut and the potentiometer.

D. Install the replacement potentiometer and connect the wires.

See the DIAGRAMS (RACKLOADER II) (8000 SRM 238) for the correct connections.

E. Adjust the potentiometer using the procedure in the Adjustments of this section.

F. Close and fasten the electrical compartment doors and the instrument panel.

C. Remove the screw and capscrew that fasten the module.

Remove the module.

REPLACING THE POWER DISCONNECT MODULE

D. Install the replacement module using the screw and capscrew. Connect wire 13 to terminal 2, wire 14 to terminal 3, wire 75 to terminal 4 and wire 74 to terminal 5.

A. Open the electrical compartment doors, disconnect the battery so that the connector is completely free and discharge capacitor C l.

E. Close and fasten the electrical compartment doors.

B. The power disconnect module is with the accelerator card below the LEDEX card. Remove the wires at the terminal strip on the power disconnect module.

NOTE The capscrews, nuts and washers that fasten the accelerator card and power disconnect module also fasten the shut-off card. This card is on the back of the electrical panel. Do not lose any of the capscrews, nuts or washers. Do not let the shutoff card fall.

INTRODUCTION GENERAL NOTE: The words “wire guidance” or “guidance” in this section describe the system of automatically steering the lift truck.

This section contains the description, operation, checks and adjustment test procedures for the parts of the wire guidance system. See WIRE GUIDANCE (Repair) (2200 SRM 321) to repair and replace the parts of the guidance system. During guidance operation the system will automatically control the electric power steering.

See the section, ELECTRIC POWER STEERING (1600 SRM 220) for the steering parts of the guidance system. All mechanical parts of the steering must be in good condition and correctly adjusted for correct guidance operation. The load wheels and casters must be the same size, in good condition and the bearings must be lubricated and correctly adjusted. The casters must also have the shims installed correctly.

to indicate the steering position and the steering direction. The automatic shut–off board will decrease the lift truck speed and stop the lift truck if the guidance system cannot sense the signal from the guide wire. The shut–off board will also stop the lift truck if there is a malfunction of a steering system component. The circuit board and the guidance push button at the instrument panel provide operator control of the guidance system. A light (LED) in the guidance push button and an alarm indicate guidance system operation. An electric generator connected to the steering wheel provides the steering input signal to the ECM when the truck is in manual steering.

DESCRIPTION (See FIGURE 1.)

The wire guidance system is designed to automatically steer the lift truck. The system senses a magnetic field from an electric signal carried by a guide wire buried in the floor. A wire driver generates the signal carried by the guide wire. The wire driver is part of the location installation and operates on AC power. For more information on the wire driver, see the WIRE DRIVER MANUAL, 599565.

The lift truck has the following guidance parts: (1) sensors at each end of the lift truck, (2) an electronic control module (ECM), (3) a steering motor, (4) a steering potentiometer, (5) an automatic shut–off board, (6) a steering generator and (7) a circuit board, guidance push button and alarm at the instrument panel for operator control of the system.

There are two sensors. One sensor is at each end of the lift truck. When the lift truck is following the guide wire, each sensor is directly over the guide wire. The sensors sense the signal from the guide wire and send signals to the ECM. The ECM controls the steering motor as indicated by the input signal. The steering motor turns the master drive unit (MDU). The steering potentiometer provides an electrical signal to the ECM

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TRACTION CIRCUIT AUTOMATIC SHUT–OFF BOARD MULITIPLE CONDUCTOR CABLE STEERING WHEEL STEERING GENERATOR CIRCUIT BOARD AT INSTRUMENT PANEL ALARM GUIDANCE BUTTON WITH LED ELECTRONIC CONTROL MODULE STEERING POTENTIOMETER BATTERY STEERING MOTOR AND GEARBOX MASTER DRIVE UNIT SENSOR (STEER WHEEL) SENSOR (LOAD WHEEL)

FIGURE 1. WIRE GUIDANCE SYSTEM Each sensor is fastened to a bracket located near the floor. The steer wheel sensor bracket is on the frame at the drive unit end of the lift truck. The bracket for the load wheel sensor is between the load wheels. The ECM

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is located in the electrical compartment. The steering motor is near the MDU. The steering potentiometer is above the MDU. The automatic shut–off board is in the electrical compartment. The circuit board at the instrument panel is fastened to the cowl plate at the instrument panel. The alarm and the guidance push button and light are also fastened to the cowl plate at the instrument panel. There is a multiple conductor cable that provides the electrical connections between the operator platform and the electrical compartment.

OPERATION (See FIGURE 2.)

NOTE: The guidance system must have a signal from the wire driver of the correct amplitude and frequency.

The standard frequency is 6 250 Hz (6 240 to 6 260 Hz) with a wire current of 78 ma (76 to 80 ma). The frequency and the wire current can each be different for each installation. Make sure the frequency and wire current from the wire driver is correct for the sensors on the lift truck. See the labels on the sensors. The Hyster wire driver has the frequency and wire current on a label inside the door. See the manufacturer for other wire drivers.

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The wire guidance system controls the electric power steering system to steer the lift truck along the guide wire. The operator will normally activate the guidance system. The guidance system can be activated or deactivated at any time, by pushing the guidance button.

The operator must steer the lift truck close enough to the wire for the system to sense the signal. If the lift truck is in a position so that the system senses the signal and the guidance system has been activated, the system will automatically find the guide wire.

NOTE: If the lift truck is correctly aligned over the guide wire when the key is turned to the ON position, the guidance system will automatically activate. The lift truck will operate on guidance until the guidance button is pushed for manual steering or automatic shut–off occurs.

Manual steering is possible when the guidance system is activated if the system cannot sense a signal. The alarm and flashing light will both operate during this condition. Steering will become automatic when the system is activated and the sensors can sense a signal.

The alarm will stop operating and the flashing light will be continuously illuminated after the lift truck is following the guide wire. The alarm and flashing light

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GUIDE WIRE LOAD WHEEL GUIDANCE SENSOR STEER WHEEL

FIGURE 2. OPERATION OF THE GUIDANCE SYSTEM

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will again operate if the guidance system loses the signal. The system will first slow the lift truck to try to sense the signal. If the guide wire signal cannot be sensed, the system will stop the lift truck and engage the brake.

The wire guidance system receives signals from the system sensors and from the steering potentiometer.

The electronic control module (ECM) uses the input signals to keep the lift truck following the path of the wire. The ECM also operates the steering motor for steering as described in the ELECTRIC POWER STEERING section. An input from the steering potentiometer tells the ECM the direction and amount of steering that occurs.

In the manual steering condition, the steering input signals come from the steering generator connected to the steering wheel. In the automatic steering condition (wire guidance), the steering input signals come from the sensors. The signal of the sensor from the guide wire is strongest when the sensor is directly over the wire.

The signal gets weaker as the sensor moves away from the wire. During normal guidance operation, the centerline of the lift truck is over the guide wire.

How To Operate The Wire Guidance System The operation of the wire guidance system is controlled by the guidance button. Pushing the button once, as the lift truck comes to the guide wire, energizes the guidance system to find the wire. This is the ”search mode” of guidance. The light in the guidance button is a flashing light and the alarm makes a noise.

For the system to find the guide wire, the lift truck must be driven at a slow speed to the guide wire. The guidance system can find the guide wire at an angle of 30 or less when traveling in the steer wheel direction.

When traveling in the load wheel direction, it is necessary to align the lift truck on the guide wire. The lift truck must be aligned within approximately 64 mm (2.5 in) of the guide wire. See FIGURE 2. Both sensors are used when traveling in the load wheel direction.

Only the steer wheel sensor is used when traveling in the steer wheel direction.

When the guidance system senses the magnetic signal from the guide wire, it automatically steers the lift truck to follow the wire. This is the “acquisition mode”. The

manual steering will not operate. If the guidance system finds the guide wire, the light in the guidance button stops flashing but remains on. The alarm stops making a noise. This is the “automatic mode”.

If the lift truck is moving too fast or is at too sharp an angle, the guidance system cannot align the lift truck on the guide wire. If this happens, the alarm continues to make noise and the light continues to be a flashing light.

The system will return to the “search mode” and it will be necessary to again manually steer the lift truck toward the guide wire.

If the guidance system finds the guide wire, the alarm continues to make noise and the light continues to be a flashing light. The guidance system automatically steers the lift truck to align it over the guide wire (“acquisition mode”). The automatic shut–off circuit is not activated and manual steering will not operate. The automatic shut–off circuit is activated after the lift truck is aligned and the alarm stops making noise. This is the “automatic mode”. At this time, the light stops flashing but remains on.

If the guidance system finds the guide wire but later loses the signal from the wire, the light flashes and the alarm makes noise. If this happens, automatic shut–off occurs. The traction circuit is deenergized and the brake is applied.

If automatic shut–off occurs, it is necessary to reset the system. Turn the key switch to the OFF position, then energize the electrical system of the lift truck for continued operation.

WARNING The guidance system will NOT be energized after the electrical system is reset unless at least one sensor is over the guide wire. Check that the guidance button light is on to operate in guidance or continue to operate in guidance. If the light is not on, push the guidance button to select guidance operation.

When a direction change is made in guidance, the light flashes and the alarm comes on for approximately 1–3 seconds. During this time the automatic shut–off function is deactivated. This permits the lift truck to make the necessary steering corrections and then automatically steer the lift truck in the opposite direction.

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NOTE: If the lift truck is correctly aligned over the guide wire when the key is turned to the ON position, the guidance system will automatically activate. The lift

truck will operate on guidance until the guidance button is pushed for manual steering or automatic shut–off occurs.

CHECKS, ADJUSTMENTS AND TEST PROCEDURES GENERAL NOTE: The checks, adjustments and test procedures in this section are for testing and adjusting the separate components. The test procedures are not in a specific sequence and this sequence is NOT a troubleshooting sequence.

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ECM CIRCUIT BOARD TEST POINTS DISPLAY LED 1 LED 2 TEST PUSH BUTTON CENTERING ADJUSTMENT FOR STEERING WHEEL SENSOR (R20) 8. RATIO POTENTIOMETER (R18) 9. CENTERING ADJUSTMENTS FOR LOAD WHEEL SENSORS (R19) 10. CENTERING ADJUSTMENT FOR TRANSDUCER (R60)

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FIGURE 3. ECM CIRCUIT BOARD

WARNING Many of the checks and adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. During some checks or

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adjustments, the operator must move the truck. The person doing the adjustments must make the adjustments with the system energized. Make sure the operator does not move the truck to cause an injury.

The wire guidance system uses the ECM test circuit to check for correct operation and adjustment of each part of the system. The test circuit automatically makes some checks during operation. Other checks can be done manually. These last checks are usually necessary as part of the adjustment procedures and are found in the ADJUSTMENTS and TEST PROCEDURES of this section. The Test push button, on the ECM circuit board, is used to change to the next manual test. The display, LED 1 and LED 2, on the ECM circuit board, indicate the results of the tests. See FIGURE 3. The ECM test circuit has the following sequence for the manual tests: 1, 2, 3, 4, 5, 6, 7, 8, 9, A and b. The display symbols for the automatic checks are described under the heading “Automatic Checks”.

To do some of the tests correctly, the center of the sensors must be directly over the guide wire. The guidance system must have a signal from the wire driver of the correct amplitude and frequency. The standard frequency is 6 240 to 6 260 Hz with a wire current of 76 to 80 ma. The frequency and the wire current can each be different for each installation. Make sure the frequency and wire current from the wire driver is correct for the sensors on the lift truck. See the labels on the sensors.

The Hyster wire driver has the frequency and wire current on a label inside the door. See the GUIDE WIRE INSTALLATION, 599596 and the WIRE DRIVER MANUAL, 599565 for the Hyster wire driver and guide wire installation. See the manufacturer for other wire drivers. The manual tests must be done on a straight section of the guide wire.

CHECKS The following paragraphs have a description of the automatic checks that are done by the test circuit of the

ECM. There is also a description of the numbers and letters on the ECM display during normal operation.

8 or another malfunction in the traction circuit can cause this display.

Automatic Checks

Normal Display (Manual Steering)

The logic system of the ECM makes internal checks for correct operation. The checks are automatic and occur during manual or automatic steering.

NOTE: When the lift truck is aligned on an energized guide wire with the guidance system activated, the guidance system will automatically steer the lift truck.

The guidance light must be off for these displays. The guidance light can go on automatically if the electrical system of the lift truck is energized when the lift truck is aligned on an energized guide wire. Push the guidance button for manual steering if this happens. The display will show one of the following numbers during manual steering.

“PROGRAM MEMORY CHECKSUM”

0 – The guidance system is set for manual steering and the steering wheel is not turning.

This automatic test checks the program memory of the ECM each time the guidance system is energized.

During the first 1/2 second after the electrical system of the lift truck is energized, the display will show an “F”.

The display will then normally show the numbers or letters described in the Normal Display description. If the display shows a “C”, the contents of the memory are not correct. The steering system will not operate and the system program needs a correction. Reset the system by moving the key to the OFF position, then energize the lift truck electrical system. If the display again shows a “C” when the system is energized, replace the EPROM on the ECM logic board.

NOTE: The display numbers in the following description are constantly changing. A single number is not on the display for very long. Read the most frequent or average of the changing numbers.

1 or more – The guidance system is set for manual steering and the operator is turning the steering wheel.

The display number multiplied by 6.25 equals steering motor current. The lift truck is NOT near the guide wire.

E – There is a steering malfunction and automatic shut–off has occurred. The traction circuit is deenergized and the brake is applied.

Normal Display (Guidance Operation)

“WATCHDOG RESET” This automatic test checks for faults that can reset the ECM during automatic steering (guidance system activated). These faults usually occur only once. The lift truck will continue to operate and the display will show an “8” to indicate a possible problem. The “8” display can be a guide to the service person if a malfunction does not occur at a regular interval. The fault can be caused by an intermittent poor connection.

“DIRECTION INPUT ERROR” This automatic test checks for possible direction input errors from the traction system. The display will show a “4” if the direction input shows that the traction system is set for Forward AND Reverse travel at the same time.

Both ECM terminals E16 and E17 have a positive voltage at the same time. A short–circuit of wires 6 and

The display will show one of the following symbols during guidance operation: 1 – The guidance system cannot sense the signal from the guide wire. The system is in the “search mode”.

Manual steering is possible. The guidance light flashes and the alarm makes a noise.

2 – The guidance system senses the guide wire (“acquisition mode”). Steering is automatic and the guidance system is steering the lift truck to the guide wire (“acquisition mode”). The guidance light flashes and the alarm makes a noise. Manual steering is NOT possible. The automatic shut–off function is NOT activated.

NOTE: The system will return to the “1” display (“search mode”) if the signal is lost before the lift truck is aligned on the guide wire. This happens if the lift truck goes beyond the guide wire and the signal is lost.

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3 – The guidance system has aligned the lift truck so that both sensors are over the guide wire (“automatic mode”). This is the normal display when the lift truck is correctly aligned with the guide wire during operation of the guidance system. The automatic shut–off is activated if the lift truck is centered within the range for the shut–off circuit. The range for lift trucks with EPROM 377725 or earlier is 38 mm ( 1.5 in). The range for lift trucks with EPROM 380436 is 25 mm ( 1.0 in). The guidance light is on (not a flashing light) and the alarm is NOT making noise. Automatic shut–off is ready to stop the lift truck if the guide wire signal is lost or a steering malfunction occurs.

4 – Automatic shut–off has decreased the travel speed of the lift truck. The centerline of the lift truck is approximately 13 to 63 mm (.5 to 2.5 in) from the guide wire. The guidance system is trying to steer the lift truck back to the guide wire.

NOTE: An upside down “E” will look like a “3” on the display. Do not check the display upside down.

5 – Automatic shut–off has occurred. The centerline of the lift truck is approxaimtely 64 mm (2.5 in) from the guide wire (EPROM 377725 or ealier). For lift trucks with EPROM 380436, the distance from the guide wire is approximately 38 mm (1.5 in). The guidance system did not get the minimum signal from the guide wire, or there is a problem with the steering system. The traction circuit is deenergized and the brake is applied.

ADJUSTMENTS General NOTE: Never adjust the guidance system if the system is operating correctly.

WARNING Many of the adjustments are done with the battery connected. Never have any metal on your fingers, arms or neck. These metal items can accidentally make an electrical connection and cause an injury.

system energized. Make sure the operator does not move the lift truck to cause an injury.

NOTE: Before any adjustments are made to the lift truck guidance system, make sure the signal from the guide wire is the correct frequency and current level.

The typical frequency is 6 240 to 6 260 Hz. The guidance system needs a guide wire current of 76 to 80 mA RMS. See the WIRE DRIVER MANUAL 599565 to check and adjust the Hyster wire Driver.

A malfunction of a separate part in the steering or guidance systems can prevent correct adjustment of the guidance system. All parts must be installed correctly and checked for correct operation. The steering chain must be correctly adjusted. See the ELECTRIC POWER STEERING (1600 SRM 220). It is very important that the MDU and steering potentiometer are adjusted for straight travel. It is also very important that the center of the steer wheel sensor is exactly over the guide wire. There must be a section of guide wire with a straight length of at least 12 meters (40 ft) long.

The operator must know how to energize the manual test function. See SET UP PROCEDURES FOR WIRE guidance in this section. Push the ECM Test button for the correct test. The ECM display will show the test number or letter. To reset the guidance system, move the key to OFF position, then energize the lift truck electrical system. Activate or deactivate the guidance system by pushing the guidance button. If the guidance system is activated, the red light in the guidance button will illuminate or flash. The alarm will make a noise when the light flashes. The battery must have a minimum specific gravity of 1.260 or the minimum given by the battery manufacturer.

SET UP PROCEDURES FOR WIRE GUIDANCE During the adjustment and test procedures you will have instructions to set the lift truck or lift truck system in a certain condition. The correct procedures are as follows: To Energize The Lift Truck Electrical System:

WARNING WARNING During some of the adjustments, the operator must move the lift truck.

The person doing the adjustments must make the adjustments with the

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Do not touch the electrical terminals of the battery connector on the battery. Electrical shock is possible. The lift truck can be operated by the operator after the battery connector is connected.

Make sure the operator does not move the lift truck to cause an injury.

To Operate The Test Function: D Energize the lift truck electrical system.

D Connect the battery to the lift truck.

D Turn the key switch to the OFF position.

D If installed, close the gates, move the key to the Start and ON position and depress the brake switch.

D Push and hold the guidance button.

To De–energize The Lift Truck Electrical System: D Disconnect the battery from the lift truck and separate the battery connector.

D Discharge the commutator capacitors in the SCR power traction or hydraulic circuts. This capacitor normally has the label “C1”.

To Activate The Wire Guidance System: D Energize the lift truck electrical system.

D Push the guidance button. The light in the button will flash and the alarm will make a noise if the lift truck is not aligned over the guide wire.

D If the lift truck is aligned over the guide wire, the guidance system will automatically activate when the lift truck electrical system is energized.

The guidance light will be on. It will not flash.

To Deactivate The Wire Guidance System: D Push the guidance button. The light will be off and the steering will be controlled by the steering wheel.

To Have The Lift Truck Operate On Guidance: D Energize the lift truck electrical system.

D Activate the wire guidance system. If the lift truck is not aligned with the guide wire, the guidance light will flash and the alarm will make a noise. This is referred to as the “search mode”.

Steering will still be controlled by the steering wheel.

D Have the operator move the lift truck to align the sensors over the guide wire. In the steer wheel direction of travel, only the steer wheel sensor needs to be over the guide wire. In the load wheel direction of travel, both sensors must be over the guide wire. When the system has found the guide wire, the guidance light will illuminate constantly. The alarm will be off and the steering wheel will NOT steer the lift truck.

D With the guidance button held down, use the key switch to the energize the lift truck electrical system.

ADJUSTMENT PROCEDURES FOR WIRE GUIDANCE SYSTEM The following instructions describe the procedures necessary to set up a lift truck equipped with the wire guidance system. The procedures MUST be done in this sequence.

Find The Centerline Of The Lift Truck 1. STEER WHEEL END – Measure the overall width of the lift truck at the steer wheel end. Mark the center of the lift truck on the outside of the frame near the floor.

2. LOAD WHEEL END – Raise the operator platform for an access to the area between the base arms. Use support beams that are long enough and strong enough to prevent the operator platform from lowering. Lower the operator platform on the support beams.

WARNING Make sure the carriage, forks or operator platform cannot lower and cause injury.

3. Measure the distance between the inside of the base arms at the bracket for the sensor. Make a mark at the center of the bracket.

4. Install a vertical pointer at both ends of the lift truck so that each pointer is aligned with the centerline of the lift truck. The point of each pointer must be approximately 13 mm (0.5 in) above the floor.

Adjustment Of The Steering Potentiometer (For Lift Trucks With An EPROM Part No. Before 377725) 1. Have the operator move the steering wheel to align the MDU in the position for straight travel. Use a ruler to check that the MDU is parallel to the frame. Measure the distance between the flat side of the MDU and the frame side plate. Measure near each vertical edge of the

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housing on the side opposite the brake. Have the opreator carefully and slowly move the steering wheel until the two measured distances are approximately the same. Use a screwdriver in the slot of the steering motor armature to make the two measured distances equal.

2. Energize the ECM test circuit and push the Test button on the ECM board for a “4” on the display.

D Make sure the lift truck is in an open area away from racks or equipment.

1. Make sure you are not in a position for injury from movement as the steer wheel turns. Energize the electrical system and the ECM test eircuit. Push the Test button on the ECM board until there is a “4” on the display.

3. If the ECM has an R60 potentiometer, adjust R60 until LED 2 on the ECM board is flashing. If the ECM does not have an R60 potentiometer, rotate the steering potentiometer housing for this adjustment.

2. Have the operator move the lift truck for slow travel in the direction of the load wheels for at least 12 metres (40 ft). Check that the lift truck moves in a straight line.

NOTE: Do not touch the terminals on the steering potentiometer while making adjustments. Touching the terminals will cause an incorrect reading.

3. If the lift truck moves in a straight line, the steering potentiometer is adjusted correctly. Do the procedure for adjusting the steer wheel sensor. If the lift truck does not move in a straight line, do step 4.

If the correct results are obtained in step 3, do the procedure for adjusting the steer wheel sensor. If the correct results are NOT obtained in step 3, go to step 4.

4. Rotate the steering potentiometer housing to the mid–point position and if the logic card has an R60, set R60 to the center position.

5. Push the Test button on the ECM for a “3” on the display. Loosen the stop screw (see FIGURE 4.). Move the steering potentiometer bracket so that the potentiometer pinion is free to rotate. Rotate the pinion of the steering potentiometer until LED 2 is flashing and the alarm makes a noise. Carefully move the potentiometer so the pinion teeth engage the gear teeth without moving the pinion any more than necessary.

LED 2 will probably stop flashing. Adjust the stop screw for a clearance of 0.8 to 1.0 mm (0.030 to 0.040 in) at the point of minimum clearance. Do steps 2 and 3.

Adjustment Of The Steering Potentiometer (For Lift Trucks With EPROM 377725 Or Later) (See FIGURE 4.)

4. If the ECM has an R60 potentiometer, adjust R60 a small amount and do step 2 again. Keep adjusting R60 and doing step 2 until the lift truck moves in a straight line. Then, do the procedure for ADJUSTING THE STEER WHEEL SENSOR in this section. If the ECM does not have an R60 potentiometer or R60 cannot be adjusted for straight travel, rotate the steering potentiometer housing for this adjustment. See FIGURE 4. and steps 5 through 7.

5. Reset the guidance system for manual steering. Have the operator move the steering wheel to align the MDU in the position for straight travel. Use a ruler to check that the MDU is parallel to the frame. Measure the distance between the flat side of the MDU and the frame side plate. Measure near each vertical edge of the housing on the side opposite the brake. Have the opreator carefully and slowly move the steering wheel until the two measured distances are approximately the same. Use a screwdriver in the slot of the steering motor armature to make the two distances equal.

NOTE: Do not touch the terminals on the steering potentiometer while making adjustments. Touching the terminals will cause an incorrect reading.

WARNING D The lift truck steering will operate automatically during this test. Make sure you are NOT in a position for an injury.

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6. Rotate the steering potentiometer housing to the center of the range of rotation. If there is an R60 on the ECM board, set R60 to the center of the range.

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1. STEERING POTENTIOMETER 2. BRACKET 3. MOUNT SCREWS (POTENTIOMETER) 4. MDU GEAR 5. POTENTIOMETER PINION 6. STOP SCREW 7. LS7 8. LS5 9. TIGHTEN TO 10 TO 11 N.m (90 TO 100 lbf in) TORQUE

10. DISPLAY 11. TEST BUTTON 12. R20 13. R18 14. R19 15. EPROM 16. R60

FIGURE 4. STEERING POTENTIOMETER ADJUSTMENT 7. Push the Test button on the ECM for a “3” on the display. Loosen the stop screw (see FIGURE 4.). Move the steering potentiometer bracket so that the potentiometer pinion is free to rotate. Rotate the pinion of the steering potentiometer until LED 2 is flashing and the alarm makes a noise. Carefully move the potentiometer so the pinion teeth engage the gear teeth without moving the pinion any more than necessary.

Adjust the stop screw for a clearance of 0.8 to 1.0 mm (0.030 to 0.040 in) at the point of minimum clearance.

Repeat steps 1, 2 and 3 of this procedure.

Adjustment Of The Steer Wheel Sensor 1. Set potentiometers R19 and R20, located on the ECM board, to their center position. To do this, turn each potentiometer 35 turns clockwise. You can normally feel the ratchet as the adjustment screw is at each end of travel. Count the number of turns from end to end and turn the adjustment screw back to the center from one end of travel. Set R18 fully clockwise.

NOTE: Some older ECM boards have potentiometers with 20 turns. Turn each potentiometer 20 turns clockwise and then counterclockwise 10 turns.

2. Align the lift truck so that it is centered over the guide wire. Connect the negative lead of a voltmeter to TP9.

Connect the positive lead of the voltmeter to terminal 8 and then to terminal 9 at connector C. Compare the two voltage readings. They must be within 0.5 volt. If the difference is more than 0.5 volt, move the steer wheel sensor to the left or right until the voltages are within 0.5 volt. The sensor must remain 66.5 mm (2.51 in) above the floor. See Figure 5.

NOTE: Do not touch the sensor when taking the voltage readings. Touching the sensor can cause an incorrect reading.

3. Push the Test button on the ECM board until an “A” is on the display. Adjust R20 for a flashing LED 1 and LED 2.

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SENSOR BRACKET GROMMET WASHER

5. NUT 6. CAPSCREW 7. FLOOR

11047

R30CH SHOWN. OTHERS SIMILAR

11558

11557

FIGURE 5. SENSOR MOUNT Adjustment For Operation Of The Guidance System In The Steer Wheel Direction

WARNING Make sure all personnel and equipment are clear of the lift truck.

NOTE: The pointers must be installed as described in ADJUSTMENT PROCEDURES FOR THE WIRE GUIDANCE SYSTEM of this section.

1. Energize the electrical system and then activate the wire guidance system.

11026

FIGURE 6. LOAD WHEEL SENSOR ADJUSTMENT

10

2. Operate the lift truck in the steer wheel direction for at least 12 m (40 ft) at a slow speed and then let the lift truck come to a stop. Do not use the brake to stop the lift

truck. Check the position of the steer wheel pointer. The point of the pointer must be over the guide wire.

3. Repeat step 2 several times. If the pointer remains over the guide wire within 6.5 mm (0.25 in), the adjustment is complete. If the pointer is constantly to the 3:00 o’clock side of the guide wire, rotate R20 clockwise. If the pointer is constantly to the 9:00 o’clock side of the guide wire, rotate R20 counter clockwise. Repeat step 2.

ADJUSTMENT OF THE LOAD WHEEL SENSOR (See FIGURE 6.)

adjustment is complete. ADJUST THE RATIO POTENTIOMETER R18. See ADJUSTMENT OF RATIO POTENTIOMETER. If the pointer is constantly to the 3:00 o’clock side of the guide wire, rotate R19 clockwise to bring the pointer over the guide wire. If the pointer is constantly to the 9:00 o’clock side of the guide wire, rotate R19 counter clockwise to bring the pointer over the guide wire.

NOTE: If adjustment of R19 does not bring the pointer over the guide wire, it will be necessary to move the load wheel sensor. Do step 4.

1. Align the lift truck so that it is centered over the guide wire. Connect the negative lead of a voltmeter to TP9.

Connect the positive lead of the voltmeter to terminal 12 and then to terminal 13 of connector plug D. See FIGURE 6. Compare the two voltage readings. They must be within 0.5 volt. If the difference is more than 0.5 volt, move the load wheel sensor to the left or right until the voltages are within 0.5 volt. The sensor must remain 66.5 mm (2.51 in) above the floor. See FIGURE 5.

4. Adjust the load wheel sensor as follows:

NOTE: Do not touch the sensor when taking the voltage readings. Contact with the sensor will cause an incorrect reading.

The support beams must be used to prevent possible injury caused by the operator platform lowering.

2. Set the lift truck for the ECM manual tests. Push the Test button on the ECM board until there is a “b” on the display. Adjust R19 potentiometer for a flashing LED 1 and LED 2. Move the key switch to the OFF position.

Adjustment For Operation Of The Guidance System In The Load Wheel Direction

WARNING Make sure all personnel and equipment are clear of the lift truck.

1. Energize the electrical system and then activate the guidance system. Operate the lift truck in the steer wheel direction for at least 6 m (20 ft) to align the lift truck with the guide wire.

2. Operate the lift truck at a slow speed in the load wheel direction for at least 6 m (20 ft). Let the lift truck come to a stop. Do not use the brake to stop the lift truck. Check the position of the load wheel pointer. The pointer must be over the guide wire.

3. Repeat step 2 several times. If the pointer remains over the guide wire within 13 mm (0.5 in), the

a. Raise the operator platform for an access to the area between the base arms. Use support beams that are long enough and strong enough to prevent the operator platform from lowering.

Lower the operator platform on the support beams.

WARNING

b. If the pointer is constantly on the 3:00 o’clock side of the guide wire, move the load wheel sensor 3–6 mm (0.13–0.25 in) to the 3:00 o’clock side of the lift truck. If the pointer is constantly on the 9:00 o’clock side of the guide wire, move the load wheel sensor 3–6 mm (0.13–0.25 in) to the 9:00 o’clock side of the lift truck. DO NOT MOVE THE LOAD WHEEL SENSOR ANY FURTHER THAN IS NECESSARY TO ALIGN THE POINTER OVER THE GUIDE WIRE.

CAUTION Do not damage the sensor by tightening the mount bolts too tight. See FIGURE 5. for the correct installation of the sensor. The sensor must not be twisted during tightening of the mount screws.

Twisting can damage the sensor.

Adjustment Of Ratio Potentiometer Use manual steering to put the center of the lift truck 50mm (2 inches) to one side of the guide wire and parallel to the guide wire. Activate the guidance system and operate the lift truck in the load wheel direction at slow speed. Check the path of the lift truck as it follows the guide wire. If the lift truck crosses the guide wire

11

several times when trying to follow the guide wire, adjust R18 two turns counter clockwise. Repeat this procedure until the lift truck is correctly following the guide wire. The setting must let the lift truck follow the guide wire without too much correction. It is easier to see corrections at a fast travel speed.

NOTE: If R18 is adjusted too far counter clockwise the lift truck can not make enough correction and will not follow the guide wire. On lift trucks that have a longer wheel base (R30CH), R18 is usually correctly adjusted fully clockwise. On trucks that have a shorter wheel base (R25A,R30C,R30CA), R18 is usually correctly adjusted to a setting less than fully clockwise.

TEST PROCEDURES It is important for the correct operation of the guidance system that all system components have electrical insulation. There must be electrical insulation between the frame of the lift truck and each component. If a connector, cable, wire or component is making a connection to the frame, a malfunction can occur. The position of a motor cable can make a magnetic field that can change the sensor signal. Electrical static can also cause a malfunction. Make sure all cables are installed in the same position that they were in before removal.

Make sure all shields are correctly installed and connected. Make sure all insulation and isolators are correctly installed. Repair all short–circuits as soon as they are found. Keep the battery and battery compartment clean and painted. Keep all carbon dust and dirt removed from the inside of all the motors. Use dry compressed air.

Checking For Short–Circuits To The Frame (See FIGURE 7.)

1. Move the lift truck away from the guide wire.

Connect the negative lead from the digital voltmeter to TP9 on ECM board. Put the positive lead on terminals 8, 9, 12 and 13 at the ECM connectors (plugs C and D).

The highest reading will be 1 volt. If the reading at any of the terminals is over 1 volt, there is a wire connection to the frame, probably in the traction circuit.

2. Do the same tests with the voltmeter as in step A. Operate the hydraulic system, the steering system and then the traction system. If the reading at any of the terminals is over 1 volt, there is a wire connection to the frame, probably in the hydraulic, steering or traction circuits.

12

3. Move the lift truck to an area that does NOT have a guide wire. Turn the steering wheel for a full right or left turn. Activate the guidance system. Accelerate the lift truck without turning the steering wheel. If the guidance system attempts to steer the lift truck out of the turn, there is a traction circuit connection to the frame. The connection makes the guidance system operate as if it were on an energized guide wire. This operating condition is usually from a high resistance connection.

A dirty battery or motor can cause this condition.

4. To check for wire connections to the frame, disconnect the battery and use an ohmmeter to check the circuits. Manually hold the power disconnect contactor contacts closed during this check. Check for 50,000 ohms or more between each terminal of the part of the battery connector on the lift truck and a clean connection on the frame. Make sure there are no electrical connections to the frame of the lift truck.

Wires or terminals without insulation can cause these connections. Isolators for circuit boards that are missing, broken or not installed correctly can also cause these connections.

5. Check for voltage between each terminal of the connector on the battery and a clean metal connection on the frame of the lift truck. It is normal to measure some voltage between the battery and the frame even if the resistance checks are correct. There can be a voltage on the frame if the battery is dirty or the battery has a defect. Clean the battery and battery compartment as necessary. There can also be a voltage on the frame if there is carbon dust in the motors. Use dry compressed air to remove the carbon dust from all motors.

Guidance Button, Alarm and Guidance Light There are two procedures to check for correct operation of the components. The first check uses the manual test of the ECM test circuit. The second procedure uses a digital voltmeter. A signal from the guide wire is not necessary for these tests.

ECM Manual Test: Energize the electrical system. Energize the ECM test circuit. Push the Test button on the ECM board. Check for a “1” on the display. Check for a flashing guidance light and that the alarm is operating. If the alarm or light does not operate, do the voltage check.

11026

FIGURE 7. SHORT CIRCUITS Voltage Check: 1. This test checks the alarm. Energize the electrical system, then activate the guidance system. Use the voltmeter to check the voltage at the alarm terminals 2B (+) and 1B (–). When the alarm is operating, the correct voltage reading is 3–12 volts. The voltage will be changing. If the voltage is correct and the alarm does not operate, replace the alarm. If the voltage is not correct, do the check for the circuit board.

2. This test checks the light (LED) in the guidance button. Energize the electrical system. Activate the guidance system. Use the voltmeter to check the voltage across terminal 1 (+) and terminal 2 (–) on terminal strip B of the circuit board. When the alarm is making a noise, the voltage is more than 1 volt. If this voltage is correct, check the voltage at the guidance button terminals.

Check for the same voltage between the wire 130 (+) and wire 131 (–) terminals on the button. If the voltage is correct and the LED is not On, replace the guidance button. If the voltage is not correct on the terminal strip B, do the check for the circuit board.

digital voltmeter. A signal from a correctly energized guide wire is necessary for these tests.

ECM Manual Test: Energize the lift truck electrical system and then activate the guidance system. Energize the ECM test circuit. A “d” will be on the display. Push the Test button on the ECM board until “1” is on the display. Use the guidance button to change the display through tests 2, 3, 4 and 5. Make sure the display goes through the numbers. If the display changes correctly, the wiring between the circuit board and the ECM board is good. If the results are not correct, do the voltmeter check.

Voltmeter Check: For the following tests, connect the positive (+) voltmeter lead to terminal 15 at the ECM connector (plug E). Connect the negative (–) voltmeter lead to TP9 at the ECM board. The lift truck electrical system must be energized for these checks.

1. In the manual steering condition, the correct voltage reading will be less than 0.5 volts.

Circuit Board and Guidance Button (See FIGURE 8.)

2. Check the voltmeter and push the guidance button.

The voltage must decrease when the guidance button is pushed. If there is no voltage change, replace the guidance button.

There are two procedures to check for correct operation of the components. The first check uses the ECM test circuit on the lift truck. The second procedure uses a

3. With the guidance system activated and the lift truck off the guide wire, the correct reading will be 3.5–4.5 volts.

13

11026

FIGURE 8. CIRCUIT BOARD AND GUIDANCE BUTTON 4. With the lift truck on the guide wire and the guidance system activated, the correct voltage reading will be greater than 4.5 volts.

If the voltage readings in steps 1, 3 or 4 are not correct, the problem is usually a defective ECM logic board.

Voltmeter Check: The following tests can be made at both the steering generator and at the ECM board. Do the checks at the ECM board first. If the tests at the ECM board are correct, the steering generator and the wiring to the ECM are good.

Steering Generator There are two procedures to check for correct operation of this component. The first check uses the ECM test circuit on the lift truck. The second procedure uses a digital voltmeter. A signal from the guide wire is not necessary for these tests.

LOAD WHEEL

ECM Manual Test: NOTE: The steer wheel will not move during this test.

Energize the ECM test circuit. Push the Test button on the ECM board until there is a “2” on the display. Check that LED 1 is on and LED 2 is off. Have the operator turn the steering wheel to steer the lift truck in the 9:00 o’clock direction first, then in the 3:00 o’clock direction. See FIGURE 9. This sequence of steering wheel rotation must be followed. The alarm will operate when the steering wheel is turned in either direction.

LED 1 must be off and LED 2 must be on when the lift truck steers toward the 9:00 o’clock direction. LED 1 and LED 2 must both be on for the 3:00 o’clock direction. If the results are not correct, do the voltmeter check. If neither LED 1 or LED 2 illuminate, do the ECM check procedure. Move the key to the OFF position.

14

STEER WHEEL 11557

FIGURE 9. LIFT TRUCK ORIENTATION 1. Energize the electrical system. Connect the positive voltmeter lead to TP4 on the ECM board. Connect the negative voltmeter lead to TP9. When the steering wheel is not being moved, the correct voltage is 2.5 volts. Turn the steering wheel quickly to steer the lift truck in the 9:00 o’clock direction. The correct voltage

reading is a positive (+) 5 volts. Turn the steering wheel quickly to steer the lift truck in the 3:00 o’clock direction. The correct voltage reading is 0 volts. If the voltage readings are not correct, do step 2.

2. Disconnect the battery connector. Connect the digital voltmeter leads between terminals 4 (+) and 5 (–) at ECM plug B. Turn the steering wheel in one direction, then the other. When the steering wheel is turned quickly, the voltage will increase. The voltage changes with the speed of steering wheel rotation. The voltage can be 4 to 5 volts. The voltage will be positive in one direction and negative in the other direction. If the voltage readings are not correct, do the same checks at the terminal strip near the steering generator. Wire 104 is (+) and wire 105 is (–). If the voltage readings are still not correct, replace the steering generator. If the voltage readings are now correct, check the wires and

11026

1.

2.

3.

4.

5.

6.

7.

8.

9.

DISPLAY TEST BUTTON LED 1 LED 2 R20 – STEER WHEEL SENSOR BALANCE POTENTIOMETER R18 – RATIO POTENTIOMETER R19 – LOAD WHEEL SENSOR BALANCE POTENTIOMETER R60 – CENTERING POTENTIOMETER POWER TERMINALS 1 – BATTERY POSITIVE (+) 2 – GEAR MOTOR 3 – GEAR MOTOR 4 – BATTERY NEGATIVE (–)

connections between the steering generator and the ECM plug B. If the voltage readings in step 1 are not correct but the readings in step 2 are correct, replace the logic board. If the steering is not correct, there can be reverse leads to the steering motor.

Electronic Control Module (ECM) (See FIGURE 10.)

The ECM must have the correct supply voltage and the fuses must be good for correct operation of the ECM. Other checks for the ECM are checks for correct inputs and outputs. See FIGURE 10. for the location of the parts on the ECM board. See FIGURE 10. when making checks and adjustments on the ECM board.

1. Energize the electrical system. Check for battery voltage between terminal 4 (–) and 1 (+) on the power terminal strip.

ZERO SPEED SIGNAL DIRECTION SIGNAL DIRECTION SIGNAL CIRCUIT BOARD AT INSTRUMENT PANEL LOAD WHEEL SENSOR (–) LOAD WHEEL SENSOR (9:00 O’CLOCK) LOAD WHEEL SENSOR (3:00 O’CLOCK) LOAD WHEEL SENSOR (+) STEER WHEEL SENSOR (–) STEER WHEEL SENSOR (9:00 O’CLOCK) STEER WHEEL SNESOR (3:00 O’CLOCK) STEER WHEEL SENSOR (+) AUTO SHUT–OFF STEERING GENERATOR STEERING GENERATOR TRANSDUCER TRANSDUCER TRANSDUCER (+)

10. FUSE 2 11. FUSE 1 12. TEST POINTS TP1 – COARSE STEER WHEEL ANGLE TP2 – FINE STEER WHEEL ANGLE TP3 – GEAR MOTOR CURRENT TP4 – STEERING GENERATOR TP5 – STEER WHEEL SENSOR OUTPUT (3:00 O’CLOCK) TP6 – STEER WHEEL SENSOR OUTPUT (9:00 O’CLOCK) TP7 – LOAD WHEEL SENSOR OUTPUT (3:00 O’CLOCK) TP8 – LOAD WHEEL SENSOR OUTPUT (9:00 O’CLOCK) TP9 – BATTERY NEGATIVE

FIGURE 10. ECM CIRCUIT BOARD

15

2. Check that FU1 and FU2 are both good. These fuses are on the power board for the ECM near the power terminal strip. Make sure the key switch is in the ON position. Use a voltmeter to check for the same voltage at each end of the fuses.

will give different readings because of internal differences in the meters. When using other meters, compare the resistance values of the transistors being tested to the resistance values of a new transistor of the same type. Allow 10% variation for correct readings.

3. Check the 5 and 12 volt supply voltage from the power board to the logic board. Deenergize the system and carefully remove the logic board from the power board. Disconnect wire 122 from terminal 2 of the power terminal strip on the ECM. Install tape on the wire to prevent a short–circuit. Measure 5 volts from the pin under the location for TP9 (–) to pin 1 and 2 of the plug below the test points. Measure at least 12 volts from the TP9 pin to pin 3 of the plug. If these voltages are not present, the power board is bad.

Checking ECM Power Transistors (See FIGURE 11. and FIGURE 12.)

1. Disconnect and separate the battery connectors.

2. Remove the ECM cover, the logic card and the power board.

3. Use a Fluke model 8060A multimeter. Set the multimeter to do the diode test as described in the Fluke instruction manual.

4. Connect the meter to each of the transistors and check for the resistance values as shown in the following table.

If any of the six readings for each transistor are not within the values shown, replace the transistor. See the WIRE GUIDANCE REPAIR (2200 SRM 321) to replace the power transistors.

NOTE: The specifications values shown were taken using a Fluke Model 8060A multimeter. Other meters

16

11869

FIGURE 11. TRANSISTOR RESISTANCE VALUES – EARLIER UNITS

1

2

3

3

4 4 5 5

6

1.

2.

3.

4.

5.

6.

TRANSISTOR BLOCK M1 TRANSISTOR BLOCK M2 C2 / E1 E2 C1 TERMINAL HOUSING 12949

TERMINAL CONNECTIONS TRANSISTOR BLOCK M1

TRANSISTOR BLOCK M2

RESISTANCE VALUES IN OHMS

POSITIVE

NEGATIVE

POSITIVE

NEGATIVE

PIN 4*

C2/E1

PIN 7*

C2/E1

80 TO 400

C2/E1

PIN 4*

C2/E1

PIN 7*

80 TO 400

PIN 4*

C1

PIN 7*

C1

450 TO 600

C1

PIN 4*

C1

PIN 7*

OPEN

C1

C2/E1

C1

C2/E1

OPEN

C2/E1

C1

C2/E1

C1

350 TO 550

PIN 6*

E2

PIN 9*

E2

80 TO 400

E2

PIN 6*

E2

PIN 9*

80 TO 400

PIN 6*

C2/E1

PIN 9*

C2/E1

450 TO 600

C2/E1

PIN 6*

C2/E1

PIN 9*

OPEN

C2/E1

E2

C2/E1

E2

OPEN

E2

C2/E1

E2

C2/E1

350 TO 550

*PIN NUMBER IN ITEM 6

FIGURE 12. TRANSISTOR RESISTANCE VALUES – LATER UNITS

17

Test Button, Display and LEDs On The ECM (See FIGURE 13.)

NOTE: When using the Test button, be sure to give the circuit time to operate on the commands. Push and hold the Test button. Then, release the button to make sure the display changes.

Energize the electrical system. Energize the ECM test circuit. Push the Test button for each of the tests (1 through 9,A,b). Make sure the display changes correctly and the LED’s illuminate. Replace the ECM board if the LEDs do not illuminate or the Test button and display do not operate correctly.

test system on the lift truck. The second procedure requires the use of a digital voltmeter. A signal from the guide wire is not necessary for these checks.

ECM Manual Test: 1. Energize the electrical system. Put the steer wheel in the position for straight travel. Energize the ECM test circuit. Push the test button on the ECM board until there is a “3” on the display. Check for the alarm signal each time the steering wheel moves past the position for straight travel. The steering position indicator light will be on each time the alarm makes a noise. If the results are not correct, do the voltmeter checks.

2. If the Part No. on the EPROM of the ECM is a number earlier than 377725, energize the electrical system and the ECM test circuit. Push the Test button on the ECM board until there is a “4” on the display. The checks are the same as in step 1.

WARNING The lift truck steering will operate automatically during this test. Make sure you are NOT in a position for an injury.

11026

3. If the Part No. on the EPROM of the ECM is 377725 or later, energize the electrical system and the ECM test circuit. Make sure you are not in a position for injury from movement as the steer wheel turns. Push the Test button on the ECM board until there is a “4” on the display. Check that the test circuit moves the MDU to the position for straight travel.

Voltmeter Checks The following tests can be made at both the steering potentiometer and at the ECM board. Do the checks at the ECM board first. If the tests at the ECM board are correct, the steering potentiometer and the wiring to the ECM are good.

FIGURE 13. ECM TEST BUTTON, DISPLAY AND LEDS Steering Potentiometer (See FIGURE 14.)

There are two procedures to check for proper operation of this component. The first checks use the diagnostic

18

1. Energize the electrical system. Connect the negative (–) voltmeter lead to TP9 on the ECM board. Connect the positive (+) voltmeter lead to terminal 1 at the ECM connector (plug A). The correct reading is 5 volts.

Connect the positive lead to terminal 3 (plug A). The correct reading is 0 volts. If the readings are not correct the problem is in the ECM board or other guidance system parts. If the readings are correct, do step 2.

11026

FIGURE 14. STEERING POTENTIOMETER

2. Connect the positive lead to terminal 2 (plug A). The correct reading is 2.5 volts when the steer wheel is straight ahead. Turn the steering wheel to steer the lift truck for a maximum turn in the 3:00 o’clock direction.

The correct reading is 1.25 volts. Turn the steering wheel fully to steer the lift truck in the 9:00 o’clock direction. The correct reading is 3.75 volts. Make sure the steering potentiometer is adjusted correctly. If the readings are not correct, do step 3.

3. Connect (+) meter lead to the connection for wire 101 at the steering potentiometer. The correct reading is 5 volts. Connect (+) meter lead to the connection for wire 103 at the steering potentiometer. The correct reading is 0 volts. If either of the tests are not correct the wires or connections are bad.

4. Put the steer wheel in the position for straight travel.

Connect the positive meter lead to the connection for wire 102 at the steering potentiometer. The correct reading is 2.5 volts. If the voltage reading is not correct the potentiometer is bad. If the voltage is not at the ECM terminal A2, wire 102 is bad.

Steering Motor (See FIGURE 15.)

Check The Steering Motor Voltage Using a Digital Voltmeter: 1. Energize the electrical system. Connect the leads of the voltmeter between terminals 1 (+) and 4 (–) at the power terminals of the ECM board. The correct reading is battery voltage. Connect the voltmeter leads between terminals 2 and 3 at the power terminals. Check the voltage while the steering wheel is turning as fast as possible. The correct voltage is 0 to 6 volts LESS than battery voltage. Stop turning the steering wheel and check for 0 volts. If the voltages are correct and the steering motor does not move, do step 2. If the voltages are not correct, check the wiring to the ECM. 2. Connect the leads of the voltmeter to the steering motor terminals. Make sure the electrical system is energized. Check the voltage as the steering wheel is turning as fast as possible. The correct voltage is 0 to 6 volts LESS than battery voltage. If the voltage reading is correct and the motor does not move, replace the steering motor.

19

11026

FIGURE 15. CHECKING THE STEERING MOTOR Check The Steering Motor Current Using The ECM Test Circuit: NOTE: The display numbers in the following description are constantly changing. A single number is not on the display for very long. Read the most frequent or average of the changing numbers.

Energize the lift truck electrical system. Have the operator move the steer wheels in the position for a maximum turn in either direction. Check the display as the operator rotates the steering wheel as fast as possible for a turn in the opposite direction. If the display has a 7, the steering motor current is too high. The maximum current is 42 Amps. The display number multiplied by 6.25 is the steering motor current. The maximum allowable current is 42 Amps.

Check The Steering Motor Current Using a Digital Voltmeter: NOTE: The following voltmeter reading is a number that is constantly changing. A single number is not on the voltmeter display for very long. Read the most frequent or average of the changing numbers.

Energize the lift truck electrical system. Connect the negative (–) meter lead to TP9 on the ECM board.

20

Connect the positive (+) meter lead to TP3 on the ECM board. Have the operator move the steer wheels in the position for a maximum turn in either direction. Check the voltmeter as the operator rotates the steering wheel as fast as possible for a turn in the opposite direction. To get the steering motor current, multiply the voltmeter reading by 10. The maximum voltmeter reading is 4.2 for a maximum current of 42 Amps.

Guidance Sensors (See FIGURE 16.)

There are two procedures to check for correct operation of the sensors. The first check uses the ECM test circuit on the lift truck. The second procedure uses a digital voltmeter. Both procedures require that there is a correct supply voltage to the sensor. Make sure there is at least 12 volts between ECM terminal C7 (+) and C10 (–) for the steer wheel sensor. There must also be at least 12 volts between terminal D11 (+) and D14 (–) for the load wheel sensor.

NOTE: The lift truck must be correctly aligned on a straight section of correctly energized guide wire for the following checks. Make sure the wire driver and sensor frequencies are the same.

11557 11026

FIGURE 16. CHECKING GUIDANCE SENSORS ECM Manual Test: NOTE: There are two sensing coils in each sensor (3:00 o’clock and 9:00 o’clock). Steps 1 through 4 check each of these coils.

1. Energize the electrical system. Energize the ECM test circuit.

2. STEER WHEEL SENSOR (3:00 o’clock) – Checks for the correct output level of the signal from the coil on the 3:00 o’clock side of the steer wheel sensor. Push the Test button until there is a “6” on the display. Operation is correct when both LED 1 and LED 2 illuminate. If the signal is too weak, only LED 1 illuminates. If the signal is too strong, only LED 2 illuminates.

3. STEER WHEEL SENSOR (9:00 o’clock) – Checks for the correct output level of the signal from the coil on the 9:00 o’clock side of the steer wheel sensor. Push the test button until there is a “7” on the display. Operation is correct when both LED 1 and LED 2 illuminate. If the signal is too weak, only LED 1 illuminates. If the signal is too strong, only LED 2 illuminates.

4. LOAD WHEEL SENSOR (3:00 o’clock) – Checks for the correct output level of the signal from the coil on

the 3:00 o’clock side of the load wheel sensor. Push the test button until there is an “8” on the display. Operation is correct when both LED 1 and LED 2 illuminate. If the signal is too weak, only LED 1 illuminates. If the signal is too strong, only LED 2 illuminates.

5. LOAD WHEEL SENSOR (9:00 o’clock) – Checks for the correct output level of the signal from the coil on the 9:00 o’clock side of the load wheel sensor. Push the test button until there is a “9” on the display. Operation is correct when both LED 1 and LED 2 illuminate. If the signal is too weak, only LED 1 illuminates. If the signal is too strong, only LED 2 illuminates.

6. Move the key to the OFF position.

Voltage Checks: NOTE: The voltage readings for the guidance sensors can change because of metal in the floor near the guide wire. Always do the voltage checks at more than one position on the guide wire.

1. Energize the electrical system. Connect the negative (–) lead of the voltmeter to TP9 on the ECM board.

Connect the positive (+) lead to terminals 8, 9, 12 and 13 of the ECM plugs. The correct voltage at each of the four

21

terminals is 1.0 – 3.0 volts. Terminals 8 and 9 are for the steer wheel sensor. Terminals 12 and 13 are for the load wheel sensor.

2. Make sure the sensors are correctly installed as shown in FIGURE 5. The sensors must have the top facing up (cable is near the top) and the cable must be on the correct side. The sensors must also be on the lift truck centerline and 65 to 68 mm (2.56 to 2.68 in) from the floor. If all of the voltage readings are low, check the signal from the wire driver. If the signal from the wire driver is correct and one of the voltage checks is not correct, replace the guidance sensor.

Automatic Shut–Off Circuit (See FIGURE 17.)

1. Move the lift truck to a section of guide wire that has a straight section.

2. Energize the guidance system of the lift truck. Make sure the guide wire is correctly energized.

3. Align the centerline of the lift truck on the guide wire.

Operate the lift truck along the straight section of the guide wire in the steer wheel direction. Stop the lift truck and disconnect wire 122 from terminal 2 of the power terminal strip on the ECM. Install tape on the wire to prevent a short–circuit.

11026

11031

FIGURE 17. CHECKING THE AUTOMATIC SHUT–OFF

22

NOTE: There are two LED indicators on the circuit board of the automatic shut–off circuit. The LEDs are under the labels BRK and SPD on the cover plate.

4. Operate the lift truck at a slow speed on guidance in the steer wheel direction.

5. Check that the lift truck slowly moves off the guide wire. The lift truck must first move at a slower speed when the centerline is approximately 38 mm (1.5 in) off the guide wire (with EPROMs before 380436). On lift trucks with EPROM 380436 or later, the lift truck will move slower when the centerline is approximately 25 mm (1 in) off the guide wire. The lift truck must stop when the centerline is approximately 64 mm (2.5 in) off the guide wire (with EPROMs before 380436). On trucks with EPROM 380436 or later, the lift truck must stop when the centerline is approximately 38 mm (1.5 in) off the guide wire. The SPD LED must go on as the lift truck moves at a slower speed. The BRK LED must go on as the brake is applied to stop the lift truck.

6. If the operation of the lift truck and the LEDs is correct, the shut–off circuit is operating correctly. If the LEDs operate correctly, but the lift truck does not move slower before stopping, check wire 30 or 31. If operation is not correct, connect wire 122 to terminal 2 of the power terminal strip on the ECM. Do the Voltage Check.

Voltage Check: 1. Energize the ECM test circuit. Connect the negative (–) lead of the digital voltmeter to TP9 on the ECM board. Connect the positive (+) lead to terminal 6 at the ECM connector (plug B). Use the Test button on the ECM board to change the display through the numbers and letters. When there is a number on the display, the correct voltage reading is less than 1 volt. When there is a letter on the display, the correct reading is 4–5 volts. If the voltage readings are not correct, replace the ECM board.

2. If the voltage readings are correct and the LEDs do not go On, check for 4 – 5 volts at terminal 4 of the shut–off board. If there is no voltage, the wire is bad. If there is voltage, check for battery voltage between terminals 8 (–) and 1 (+). If these voltage readings are correct and the shut–off circuit does not stop the lift truck, replace the auto shut–off board.

Test Point Checks (See FIGURE 18.)

The following voltage readings are taken at the eight test points (TP) on the ECM board.

Connect the negative lead of the digital voltmeter to TP9 for all of these checks. Connect the positive lead to the correct test point for each test.

11557 11026

FIGURE 18. TEST POINT CHECKS

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TP1 – The lift truck must be set for manual steering. The correct reading is 2.5 volts when the steer wheels are in the position for straight travel. Have the operator move the steering wheel for a full turn in the 9:00 o’clock direction. The correct voltage is approximately 5 volts.

Have the operator move the steering wheel for a full turn in the 3:00 o’clock direction. The correct voltage is approximately 0 volts.

TP2 – The lift truck must be set for manual steering. The correct reading is 2.5 volts when the steer wheels are in the position for straight travel. Have the operator move the steering wheel so that the MDU is 16 for a turn in the 3:00 direction from the straight position. The correct voltage is 0 volts. Have the operator move the steering wheel so that the drive units are 16 for a turn in the 9:00 o’clock direction from the straight position. The correct voltage is 5 volts.

TP7 and TP8 – When the load wheel sensor is centered over a correctly energized guide wire, the readings from these two points will be within 0.5 volt. If the ECM manual test checks are correct, these readings will be correct.

ECM Signal Checks (See FIGURE 19.)

ECM Manual Test: 1. Energize the electrical system. Energize the manual test function and push the ECM Test button for a “5” on the display. Check that LED 1 illuminates and LED 2 is off.

WARNING The steer wheel must be in the position for straight travel. The lift truck must move for this test. Make sure no person is in the path of the lift truck.

TP3 – The voltage reading mulitiplied by 10 equals steering motor current.

NOTE: Make sure the drive wheel does not spin or slip during these checks.

TP4 – The correct reading is 2.5 volts, when not steering. When turning the steering wheel quickly in one direction, the correct reading is 0 volts. When turning the steering wheel quickly in the other direction, the correct reading is 5 volts.

2. Have the operator slowly move the speed and direction controller for a slow travel speed in the steer wheel direction. LED 1 must go off and LED 2 must illuminate while the lift truck is moving. Have the operator move the speed and direction controller for a slow speed in the load wheel direction. Both LED 1 and LED 2 must illuminate as the lift truck stops (plugging) and while the lift truck is moving in the load wheel direction. If there is no zero–speed (end of plug) signal, LED 1 stays on and LED 2 goes off. There is no adjustment for these signals.

TP5 and TP6 – When the steer wheel sensor is centered over a correctly energized guide wire, the readings from these two points will be within 0.5 volt. If the ECM manual test checks are correct, these readings will be correct.

11557 11026

FIGURE 19. ECM SIGNAL CHECKS

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Voltage Check Using A Digital Voltmeter: 1. Energize the electrical system. Connect the negative lead of the voltmeter to TP9 on the ECM board. Connect the positive lead to terminal 16 at the ECM connector (plug E). Rotate the speed and direction controller in the steer wheel direction. The correct reading is at least 70% of battery voltage.

2. Connect the positive voltmeter lead to terminal 17 at the ECM connector (plug E). Rotate the speed and direction controller in the load wheel direction. The correct reading is at least 70% of battery voltage.

3. When the positive voltmeter lead is connected to either terminal 16 or 17 (plug E) and the speed and

direction controller is in the Neutral position, the correct reading is less than 0.5 volt.

WARNING The lift truck must move during the next test. Make sure no person is in the path of the lift truck.

4. Connect the positive voltmeter lead to terminal 18 at the ECM connector (plug E). Rotate the speed and direction controller in either direction for a slow speed.

Rotate the speed and direction controller in the opposite direction (plugging). The correct voltage reading during plugging is 6 volts or more.

5. If any of the voltage checks are not correct, check the wiring and components of the traction circuit for the problem.

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FIGURE 1. HYDRAULIC SYSTEM SCHEMATIC

FIGURE 2. ELECTRICAL SCHEMATIC

FIGURE 3. ELECTRICAL WIRING DIAGRAM (TRUCK)

FIGURE 4. ELECTRICAL WIRING DIAGRAM (OPERATOR PLATFORM)

FIGURE 5. ELECTRICAL DIAGRAM