IBM ThinkPad T20, Hardware Maintenance Manual

Page: 49 / 108

Symptom-to-FRU index
Undetermined problems
You are here because the diagnostic tests did not identify
which adapter or device failed, wrong devices are installed,
a short circuit is suspected, or the system is inoperative.
Follow these procedures to isolate the failing FRU (do not
isolate FRUs that have no defects).
Verify that all attached devices are supported by the
computer.
Verify that the power supply being used at the time of the
failure is operating correctly. (See “Power system
checkout” on page 26.)
1. Power off the computer.
2. Visually check each FRU for damage. Replace any
damaged FRU.
3. Remove or disconnect all of the following devices:
a. Non-IBM devices
b. Devices attached to the port replicator
c. Printer, mouse, and other external devices
d. Battery pack
e. Hard-disk drive
f. External diskette drive
g. DIMM
h. CD-ROM and diskette drive in the Ultraslim Bay
i. PC Cards
4. Power on the computer.
5. Determine whether 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 FRUs
one at a time (do not replace a nondefective FRU):
a. System board
b. LCD assembly
ThinkPad T20
45