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To Remove the Snubber Resistors:
1. Disconnect the upper and lower "L" brackets to
the DC link with a 3/4" inch socket. Remove only
the outer four "L" brackets on the snubbers and
leave the brackets on the center two snubbers.
Note: The brackets on the two center snubbers must
remain in place to prevent the DC link from falling.
2. Remove the cables to the DIT located on the "L"
brackets.
3. Remove the snubber mounting bolts with a 3/4"
inch socket.
4. Remove the snubber assembly. The threaded rod
pulls out with the snubber assembly. To remove
the top left snubber assembly, loosen the bolts on
the bracket securing the left side of the link and
then push the link up to get the snubber assembly
out.
5. Remove the four screws holding the resistor to the
base. (These screws have been installed and
®
retained with Loctite
, and will require extra force
to remove.)
6. Remove the rubber grommet along with the resis-
tor cables.
7. Remove the resistor from the base and remove
and discard the gaskets.
Snubber Resistor Installation
1. To pull the new resistor cables through the hole
in the base, spray the cables with ether or alcohol
near the new grommet so that it slides easier in
place. Do not RTV the new grommet.
2. Using RTV 6708, seal the corners of the resistor
where it contacts the snubber base to prevent air
leakage at the seams.
3. Install a flat washer over each mounting hole
between the base and the gasket.
4. Install new inner and outer gaskets. Using RTV
6708, seal the seam between the outer gasket
and the two inner gaskets.
®
5. Apply Loctite
to the four mounting screws for the
snubber resistors and install the resistors on the
base.
6. Install the snubber assembly in the truck, making
sure the resistor wires are on top.
E03015 3/01
AC Drive System Electrical Checkout Procedure
(Release 17 Software)
7. Install the four mounting bolts for each snubber
resistor assembly. Tighten to 65 ft. lbs. (88 N.m)
torque.
8. When the outer snubber assemblies are installed,
reinstall the "L" brackets.
9. Following a similar procedure as explained above,
replace the resistors on the center top and bottom
snubber resistor assemblies.
Phase Module Installation
1. Return each Phase Module to its original location.
2. Apply two full twists on the snubber cables prior
to connecting it to the phase modules. Put a tyrap
at each twist.
3. Secure each snubber cable to the capacitor box
on top of each phase module with a tyrap.
4. Tighten the four 5/8"-11 Phase Module mounting
bolts to 111-124 ft. lbs. (150 - 168 N.m) torque.
5. Reconnect the fiber optic cables and the plug at
the top of each Phase Module.
6. Replace the front cabinet supports between the
doors.
7. Remove the ground jumpers from the DC link.
8. Close battery disconnect switches to reconnect
the truck batteries.
E3-37
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Table of Contents
Troubleshooting
