Model 9600/9700 Swing-Reach ® Lift Truck

To test, measure the resistance from the FGND screw to any piece of bare metal on the frame with a DMM. Resistance should be <0.5ohm.

Section 5.Troubleshooting Electrical Troubleshooting

Inrush Protection

A resettable fuse protects the VM battery sense circuit and can be reset by turning the truck OFF momentarily. Opening of the fuse will frequently manifest as an FH code along with other F-series codes.

NOTE: This test should be performed after the truck has had a chance to come to room temperature.

To test, remove JPF4 from the Fuse/Relay Card. Measure the resistance from PF4-1 to PF4-7. Resistance should be approximately 1.3 ohms. Replace the Fuse/Relay Card as necessary.

DC Motors

Types of DC Motors

Input Diodes

NOTE: Remove connectors JP1 thru JP4 before performing this test.

To test the relay coil input diodes, locate CR5 and CR6 on the Fuse/Relay Card. Using a DMM set to the “diode” function, measure the voltage by putting the black probe on the banded (right) side of the diode and the red probe on the nonbanded (left) side. Voltage should be approx. 0.5V across each diode. An open circuit will be displayed if the diodes are tested in the reverse direction. Replace the Fuse/Relay Card as necessary.

There are two primary types of DC Motors: •A series-wound motor has only two external connections because the armature and field windings are connected internally.

Figure 5-7.Series-Wound Motor Circuit

•A permanent magnet motor has two external connections. The field is produced by an internal magnet.

Publication: 1089040, Issued: 08 Apr 2016 5-15

Section 5.Troubleshooting

Electrical Troubleshooting

NOTE: Field connections may be labeled A or S. Series wound motor field connections may be labeled D.

Inspection

Inspect commutator for surface condition and high mica. Most armatures have the mica undercut. If the armature on your motor does not, do not attempt to cut it.

Model 9600/9700 Swing-Reach ® Lift Truck

commutator bars, remove the motor for servicing.

Servicing

Some conditions identified in Table5-3 may be resolved by cleaning the commutator with a special polishing stone. Polishing the commutator should only be attempted for these specified conditions. Refer to “Polishing the Commutator” on page7-54 .

Some conditions can be resolved by recutting the commutator on a lathe. This requires special equipment and training and should only be performed at a qualified DC motor repair facility.

The commutator must be smooth and clean to provide maximum brush wear. When commutators are not correctly maintained, carbon dust can collect in the grooves between the segments. This can lead to a short circuit in the armature.

Remove the brushes from their box. Inspect the contact surface and brush length. If brush surface has grooves or pit marks, it indicates a burr on the commutator surface.

Good commutation is indicated by a dark brown polished commutator and an evenly polished brush wearing surface. See Table5-3, “Commutator Surfaces.”

If the commutator appear s rough, pitted, or has signs of burning or heavy arcing between the

Publication: 1089040, Issued: 08 Apr 2016