80 Chapter 4
Intermittent Problems
Intermittent system hang problems can be caused by a variety of reasons that have not hing to do with a
hardware defect, such as: cosmic radiation, electrostatic dischar ge, or software errors. FRU replacement
should be considered only when a recurring problem exists.
When analyzing an intermittent problem, do the following:
1. Run the advanced diagnostic test for the main board in loop mode at least 10 times.
2. If no error is detected, do not replace any FRU.
3. If any error is detected, replace the FRU. Rerun the test to verify that there are no more errors.
Undetermined Problems
The diagnostic problems does not identify which adapt er or d evice f ailed , which instal led de vices ar e i ncorr ect,
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 comp uter.
NOTE: Verify that the power supply being used at the time of the failure is operating correctly. (See “Power
System Check” on page 71):
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:
!Non-Acer devices
!Printer, mouse, and other external devices
!Battery pack
!Hard disk drive
!DIMM
!CD-ROM/Floppy diskette drive Module
!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:
!Main Board
!LCD assembly