Tweco 81 with SL100SV - Manual (Page 101)

Manual 0-4641 5-37 SERVICE
5
C. Logic PC Board Replacement
Follow the antistatic instructions provided with the replacement part. The Logic PC Board connects to the Main PC
Board through an extender board perpendicular to both boards.
1. Remove the power supply cover per Section 5.09-A.
2. Remove the bolts in each corner of the Logic PC Board.
3. Detach the Logic PC Board and the extender board from the Main Power PC Board. Detach the extender board from the
Logic Board.
4. Install the replacement Logic PC Board by reversing the above steps. The pins on the right edge of the Logic PC Board
must fully engage the sockets on the edge of the extender board. The extender board must fully engage sockets on the
Main Power PC Board.
D. IGBT Circuit Board or Input Diode Board Replacement
Follow the antistatic instructions provided with the replacement part. The Power Supply includes two IGBT Circuit PC Boards.
NOTE
Follow the electrostatic discharge instructions provided with the replacement component to prevent damage to
the component.
Thermal pads, heatsinks, and the large flat surface on the back of diodes and IGBTs must be kept clean. Diodes and
IGBTs must not be bent or allowed to pick up any foreign material. A very clean installation between the module
and the heatsink or chassis is essential for proper operation.
1. Remove the power supply cover per Section 5.09-A.
2. Turn the Power Supply onto its side.
3. Locate the IGBT Circuit PC Boards or Input Diode mounted within the Main Power PC Board. Refer to Appendix pages
for location and position.
4. For IGBTs, remove the small jumpers between the IGBT and the Main PC Board. Transfer these jumpers to the replace-
ment IGBT. Label, then remove all other wire connections to the Board(s) being replaced. Note the routing of wires.
Ensure that the wires are put back in the same place when installing the replacement module.
5. Remove screw(s) securing PC Board(s) to the heatsink and remove board(s) from the Power Supply.
6. Use isopropyl alcohol and a clean rag to clean the heatsink or chassis area behind the component being replaced. Clean
the large flat surface on the back of the replacement component. Do not scratch or abrade the surface.
7. The thermal pad(s), provided with the replacement part, is a thin metal pad. Remove any loose protective paper coverings
from the pad(s).
NOTE
Protective coverings must be removed from the thermal pads. Installing thermal pads with protective coverings in
place will cause equipment damage or failure.