Display = “A” Head Capacitor
Display = “F&2” Drive System Failure
The head capacitor ensures that a steady voltage is maintained to the positive heatsink and that large voltage spikes are filtered out. The logics monitors this at P2-4. If it detects that the head capacitor has failed, an “A” will be displayed and truck performance will be reduced.
The logics at P12-6 uses wire #37 from the emitters of the drive transistors to detect if the drive transistors, bypass contactor tips or the driver board are shorted. In normal operation P12-6 has battery voltage only when the logics is pulsing the drive transistors or the bypass contactor is activated. When a failure occurs, the line contactor will be deactivated and an “F&2” will flash on the display.
Display = “E” [Flashing] Key On, No Operator Warning
Display = “F&3” Hydraulic Pump System Failure
Anytime the battery is connected, the key is turned to ON and no one is in the seat longer than the value set in programmable feature “6” (Seat Switch Timer), the letter will flash on and off. The truck will not operate until the seat switch is closed.
The logics at P12-7 uses wire #45 from the emitters of the pump transistors to detect if the pump transistors, pump contactor tips or the driver board are shorted. In normal operation P12-7 has battery voltage only when the logics is pulsing the pump transistors or the pump contactor is activated. When a failure occurs, the line contactor will be deactivated and an “F&3” will flash on the display.
Display = “E” [Not Flashing] Static Return To Off (SRO) The logics has a Static Return to Off (SRO) circuit which assures that the direction switch has been returned to neutral, the accelerator returned to the full up position and the park brake to OFF after the key and seat switches are closed. This safeguards against an accidental actuation of direction and speed when an operator resumes operation of an idle truck. If SRO occurs, the direction lever can be moved to neutral and/or the accelerator pedal released. The direction can now be reselected and the accelerator pedal depressed to start normal lift truck drive operation.
Display = “F&4” Hydraulic Pump and Drive System Failure The logics will release the line contactor and flash “F&4” on the display when BOTH wires #37 and #45 detect battery voltage when it should not be present. See “F&2” and “F&3”. Display = “F&5” Drive system Failure The logics at P12-6 uses wire #37 from the emitters of the drive transistors to detect battery negative. The logics sends a test pulse out to the drive transistors when powered up. This test pulse is detected at P12-6 also. If battery negative is present or the test pulse is not detected, the line contactor will be deactivated and an “F&5” will flash on the display.
Display = “F” Logic Board Failure The logics can detect some internal circuit failures. When a failure is detected, an “F” appears on the display. Display = “F&1 - F&b” Failure Protection Circuits
Display = “F&6” Hydraulic Pump System Failure
The Failure Protection Circuits guard against conditions that could cause the operator to lose control of the truck. If one of the circuits is activated, the display will alternately flash the letter “F” and a number or a second letter. The logics will deactivate the line contactor and prevent normal operation of the truck.
The logics at P12-7 uses wire #45 from the emitters of the pump transistors to detect battery negative. The logics sends a test pulse out to the pump transistors when powered up. This test pulse is detected at P12-7 also. If battery negative is present or the test pulse is not detected, the line contactor will be deactivated and an “F&6” will flash on the display.
Display = “F&1” Accelerator System Failure The logics at P1-7, 8, 9 and 10 uses wires #11, 10, 9 and 8 to determine accelerator position. If the logics detects a change in the accelerator position from OFF (pedal fully released) to ON (pulsing or bypass operation) without going through the first pulsing position, the line contactor will be deactivated and an “F&1” will flash on the display.
MicroCommand Control System
Display = “F&7” Hydraulic Pump and Drive System Failure The logics will release the line contactor and flash “F&7” on the display when BOTH wires #37 and #45 detect battery negative or do not detect the proper pulsing. See “F&5” and “F&6”.
23
Systems Operation
