Thermo Scientific Oretronic III, Operating & Service Manual

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Maintaining & Troubleshooting
Thermo Fisher Scientific Maintaining & Troubleshooting 4-25
REC-4105 Rev L
If the displays do not light, the TMD has been damaged and must
be replaced.
If the fuse tested bad in the first procedure:
1. Replace the fuse with the correct sized fuse.
2. Turn the power switch back on.
3. If the displays do not light, turn the power switch off.
4. Test the fuse again.
If the fuse tests good, follow Steps 8–10 in the first test procedure.
If the fuse tests bad, continue with this procedure.
5. Disconnect all wiring to the CPU board except the power on TB1.
6. Replace the fuse with the correct-sized fuse.
7. Turn the power switch back on.
8. If the displays do not light, turn the power switch off.
9. Test the fuse again.
If the fuse tests good, follow Steps 8–10 in the first test procedure.
If the fuse tests bad, the TMD has been damaged and must be replaced.
The previous procedure should leave you with a functioning display
with no field wiring except incoming power. The next test is to
determine whether a peripheral system component may be causing the
fuse to blow.
You will be connecting components to the CPU board one at a time until
the fuse blows. Refer to the field wiring diagram for your system or the
Field Wiring Diagram (D07344A-E001) in Appendix D for correct
wiring connections.