Chapter 4 67Keyboard or Auxiliary Input Device CheckRemove the external keyboard if the internal keyboard is to be tested.If the internal keyboard does not work or an unexpected character appears, make sure that the flexible cableextending from the keyboard is correctly seated in the connector on the system board.If the keyboard cable connection is correct, run the Keyboard Test. See “System Diagnostic Diskette” on page40 for details.If the tests detect a keyboard problem, do the following one at a time to correct the problem. Do not replace anon-defective FRU:1. Reconnect the keyboard cables.2. Replace the keyboard.3. Replace the system board.The following auxiliary input devices are supported by this computer:T Numeric keypadT External keyboardIf any of these devices do not work, reconnect the cable connector and repeat the failing operation.Memory CheckMemory errors might stop system operations, show error messages on the screen, or hang the system.1. Boot from the diagnostics diskette and start the PQA program (please refer to “System DiagnosticDiskette” on page 40.2. Go to the diagnostic memory in the test items.3. Press m in the test items.4. Follow the instructions in the message window.NOTE: Make sure that the DIMM is fully installed into the connector. A loose connection can cause an error.Power System CheckTo verify the symptom of the problem, power on the computer using each of the following power sources:1. Remove the battery pack.2. Connect the power adapter and check that power is supplied.3. Disconnect the power adapter and install the charged battery pack; then check that power is supplied bythe battery pack.If you suspect a power problem, see the appropriate power supply check in the following list:T “Check the Power Adapter” on page 68T “Check the Battery Pack” on page 69