4-16 TroubleshootingIntermittent Problems 0Intermittent system hang problems can be caused by a variety of reasons that havenothing to do with a hardware defect, such as: cosmic radiation, electrostatic discharge,or software errors. FRU replacement should be considered only when a recurringproblem exists.When analyzing an intermittent problem, perform 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 an error is detected, replace the FRU. Rerun the test to verify that there are nomore errors.Undetermined Problems 0The diagnostic problems do not identify which adapter or device failed, which installeddevices are incorrect, whether a short circuit is suspected, or whether the system isinoperative.Perform the following procedures to isolate the failing FRU (do not isolate non-defective FRU).NOTE:NOTE:Verify that all attached devices are supported by the computer.NOTE:NOTE:Verify that the power supply being used at the time of the failure is operatingcorrectly. (Refer to Power On Issues).1. Remove power from the computer.2. Visually check components for damage. If any problems are found, replace the FRU.3. Remove or disconnect all of the following devices:z Non-Acer devicesz Printer, mouse, and other external devicesz Battery packz Hard disk drivez DIMMz CD-ROM/Diskette drive Modulez PC Cards4. Apply power to the computer.5. Determine if the problem has changed.6. If the problem does not recur, connect the removed devices one at a time until failingFRU is found.7. If the problem remains, replace the following FRUs:z System boardz LCD assembly
