Acer TravelMate 4020, Service Manual, Page: 85 / 106

Chapter 4 79
Undetermined Problems
The diagnostic problems does not identify which adapter or device failed, which installed devices are incorrect,
whether a short circuit is suspected, or whether the system is inoperative.
Follow these procedures to isolate the failing FRU (do not isolate non-defective FRU).
NOTE: Verify that all attached devices are supported by the computer.
NOTE: Verify that the power supply being used at the time of the failure is operating correctly. (See “Power
System Check” on page 65):
1. Power-off the computer.
2. Visually check them for damage. If any problems are found, replace the FRU.
3. Remove or disconnect all of the following devices:
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Non-Acer devices
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Printer, mouse, and other external devices
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Battery pack
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Hard disk drive
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DIMM
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CD-ROM/Diskette drive Module
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PC Cards
4. Power-on the computer.
5. Determine if the problem has changed.
6. If the problem does not recur, reconnect the removed devices one at a time until you find the failing FRU.
7. If the problem remains, replace the following FRU one at a time. Do not replace a non-defective FRU:
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System board
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LCD assembly