Packard Bell EasyNote LJ75, Service Manual

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Chapter 4 159
Motherboard CMOS Discharge
If any problems such as incorrect CMOS settings, the CMOS data can be cleared by short-circuiting the
CMOS CLRP2 jumpers. Open the memory bay door and short-circuit the jumpers near the DDR socket, using
a metal conductivity tool.
Intermittent Problems
Intermittent system hang problems can be caused by a variety of reasons that have nothing to do with a
hardware defect, such as: cosmic radiation, electrostatic discharge, 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 system 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 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 On
Issue” on page 140.):
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/Diskette drive Module
• PC Cards
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