Chapter 4: Troubleshooting 153Undetermined problemsIf the diagnostic test may not identify which adapter or device failed, which installed devices areincorrect, whether a short circuit is suspected, or whether the system is inoperative. Use theseprocedures to isolate the failing FRU (do not isolate a non-defective FRU).Note: Verify that all attached devices are supported by the notebook.Note: Verify that the power supply being used at the time of the failure isoperating correctly. (See “Testing the power system” on page 138.):To isolate a failing FRU:1 Turn off the notebook.2 Visually check FRU parts for damage. If you identify any damage, 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(s)❑ SO-DIMM❑ Optical drive❑ PC Cards and Type 54 ExpressCards4 Turn on the notebook.5 Determine if the problem has changed.❑ If the problem does not recur, reconnect the removed devices one at a timeuntil you find the failing FRU.❑ If the problem does recur, replace the following FRUs one at a time:❑ System board❑ LCD assemblyImportant: Do not replace a non-defective FRU.
