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• • • • BE CERTAIN TO ALLOW ADEQUATE TIME
FOR LINK VOLTAGE TO DRAIN DOWN be-
fore opening the electrical cabinet to per-
form the following checks or repairs.
Verify the Blower Control Panel (AXCAP)
LED's (4, Figure 3-9) are OFF.
• • • • If any of the above warning lights remain
ON, a system failure may have occured.
Refer to "Truck Shutdown Instructions—
Shutdown After System Failure" for proce-
dures to follow before attempting repairs.
Troubleshooting Phase Modules and
Chopper Modules
1. To troubleshoot a phase module or chopper mod-
ule, access the PSC Manual Test screen on the
PTU while connected to PSC panel, engine
stopped, and NOT in rest mode.
2. Move cursor to the appropriate GD1E or GD2E
signal in the digital output area and turn it ON.
(GD1E turns on all Inverter 1 phase modules and
chopper module 1. GD2E turns on all Inverter 2
phase modules and chopper module 2.)
3. Disconnect the GRAY fiber optic cable on the
phase module or chopper module being checked.
4. There should be red light visible out of the GRAY
receptacle on the gate drive module.
5. If there IS red light, the phase module or chopper
module is OK.
6. If red light IS NOT visible, disconnect the round
power supply harness from the gate drive mod-
ule.
7. Check the AC voltage in the two pins in the
harness;
There should be 100 VAC square wave on the
harness. The actual reading on the VOM will
depend on the meter and how it is designed to
measure AC voltage. Most meters read less than
100 volts. Normally, there will either be proper
voltage on the harness or NO voltage at all on the
harness.
8. If there is NO voltage, troubleshoot the Gate Drive
Power Converter (GDPC) or the harness.
E3-36
MISCELLANEOUS COMPONENT REPAIR
AC Drive System Electrical Checkout Procedure
(Release 17 Software)
9. If there IS voltage, reconnect the harness and
disconnect the GTO Gate lead on the "G" termi-
nal.
10. If there IS red light visible with the gate lead
disconnected, the GTO is shorted and the entire
phase module or chopper module must be re-
placed.
11. If there IS NOT red light visible with the gate lead
disconnected, the GATE DRIVE MODULE is
faulty and should be replaced.
All the gate drive sections for phase modules and
chopper modules are alike and interchangeable.
The Red-covered and White-covered gate drive
modules are interchangeable where mounted by
the 6 capscrews to the cooling tubes of the phase
module or chopper module.
Phase Module Removal and Snubber
Resistor Replacement
To Remove the Phase Modules:
1. Open the battery disconnects to disconnect the
truck batteries.
2. Short out the DC link by installing jumpers from
(+) to (-) next to the AFSE and then to ground.
3. Remove the front cabinet supports between the
doors.
4. Disconnect the fiber optic cables and the plug at
the top of each Phase Module. Tuck the removed
cables under the blue loom to protect the cables
when the modules are pulled out.
5. With a 15/16" inch socket, remove the four mount-
ing nuts on each Phase Module.
6. Cut the tyrap by the capacitor on top of each
Phase Module.
7. Partially pull out each Phase Module. Using a
7/16" inch socket, remove the snubber wire be-
hind the top capacitor.
8. Remove each Phase Module which weighs 65
pounds (29.5 Kg). Mark each Module so that it will
be put back in the same location that it was
removed from.
3/01 E03015
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Table of Contents
Troubleshooting
