Lenovo ThinkPad 760CD ThinkPad 380, 385, 560, 560E, all 760, 765 and SelectADo - Page 459

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 the 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 FRUs. 3. If any error is detected, replace the FRU shown by the FRU code. Rerun the test to verify that no more errors exist. Undetermined Problems You are here because the diagnostic tests did not identify which adapter or device failed, installed devices are incorrect, a short circuit is suspected, or the system is inoperative. Follow these procedures to isolate the failing FRU (do not replace nondefective FRUs). Verify that all attached devices are supported. Verify the power supply being used at the time of the failure is operating correctly. (See "Power Systems Checkout" on page 422.) 1. Power off the computer. 2. Check the cables, wires, and connectors for short/open circuits, and visually check for damage. If a problem is found, replace the FRU. 3. Remove or disconnect all of the following devices: a. Non-IBM devices b. Devices at the expansion bus connector c. Printer, mouse, and other external devices d. Battery pack e. Hard disk drive f. Diskette drive or CD-ROM drive g. DIMM h. PC Cards 4. Power on the computer. 5. Determine if the problem has changed. 6. If the problem does not reoccur, 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. DC/DC card Video card Keyboard card LCD assembly System board DSP card or audio (ESS) card CPU card ThinkPad 765D (9546), 765L (9547) 447