GEAR (36 Teeth) 5D1764 - Caterpillar

Table 2
Positive Power Transistor Gate ON Voltage Drop Checks
(Meter set to "Diode" scale)    
    AC     P (DCP)     Expected Meter Reading    
Meter Probe Position     NEG (2)     POS (1)     Less than 0.5V DC    
POS NEG     Less than 0.5V DC    
( 2 ) NEG = negative multimeter probe.
( 1 ) POS = positive multimeter probe.
Table 3
Negative Power Transistor Gate ON Voltage Drop Checks
(Meter set to "Diode" scale)    
    N     AC     Expected Meter Reading    
Meter Probe Position     POS (1)     NEG (2)     Less than 0.5V DC    
NEG POS     Less than 0.5V DC    
( 1 ) POS = positive multimeter probe.
( 2 ) NEG = negative multimeter probe.
If any of the voltage drop checks that are listed in the table do not agree with the values in the "Expected Meter Reading" column, the indication is that there is a problem in the phase module. Repeat this test in order to confirm the results. If the results again indicate that there is a problem in the phase module, inform your dealer Technical Communicator (TC) for possible consultation with Caterpillar. This consultation will provide instructions on the action that must be taken to resolve this problem.
If the results of the voltage drop check match the values in the "Expected Meter Reading" column, The testing or the troubleshooting for the transistor is finished, press the "NEXT" button in order to select another transistor to test. The check mark or the highlight will remain on the transistor line that has been tested.
Repeat the steps starting at Step 5 in order to check another power transistor and the circuits.
Press the "CANCEL" button in order to exit the test at any time.Troubleshooting the Power Transistor Circuits
Note: When a specific power transistor circuit has been energized, the user must verify the results of the testing. Disconnect the fiber optic connectors and observe the presence or absence of the light pulses. The light will appear as a steady red tinted light. Do not look directly into the fiber optic circuit when the circuit is energized. For the copper sections of the circuits, a voltage check will be used to verify correct operation.The following troubleshooting tips will help to determine if there is a problem in the transistor circuits or a problem with a component.
Illustration 10 g01958551
Phase module low voltage connector (12) Fiber optic driver circuits are located at contact "B" and "R" (13) Fiber optic feedback circuits are located at contacts "C" and "S"
When the transistor driver circuit is energized by the motor control ECM, a steady red tinted light should be seen at any of the disconnected fiber optic connectors at the interface module or the phase module. If the light is not present, follow the circuit back to the optical source in order to isolate the cause of the problem.
The fiber optic circuits and connectors are not serviceable. If a problem is found