IBM 2621421 Hardware Maintenance Manual - Page 36

DIMM 32MB 128MB 64MB 128MB DIMM 128MB 64MB 128MB 128MB Total Memory 160MB 192MB 192MB 256MB CAUTION: This system cannot work without DIMM memory. Memory errors might stop system operation, show error messages on the screen, or hang the system. Use the following procedure to isolate memory problems: Note: Make sure that the DIMM is properly installed into the connector. A loose connection can cause an error. 1. Power off the computer and replace the DIMM. 2. Boot from the diagnostics diskette and start the PQA program (please refer to "Running the PQA Diagnostics Program" on page 49). 3. Run the Memory item to run the memory test. If no error appears, install a new DIMM; if an error appears, replace the system board. Keyboard and External Input Device Check Note: If an external keyboard is attached, remove it if the internal keyboard has to be tested. If the internal keyboard does not work or an unexpected character appears, make sure that the flexible cable extending from the keyboard is correctly seated in the connector on the TrackPoint board. If the tests do not detect a keyboard problem, run the Keyboard test by doing the following: 1. Boot from the diagnostics diskette and start the PQA program (please refer to "Running the PQA Diagnostics Program" on page 49). 2. Go to Diag and select Manual Test, then choose Keyboard from the Test Item and press F2 to execute. 3. Check that when each key is pressed, the key's position on the keyboard layout on the screen changes to a black square. Note: Press Y+Enter to close the test. If the test detects a keyboard problem, do the following one at a time to correct the problem. Do not replace a nondefective FRU. Ensure the keyboard switch is correctly set. 28 ThinkPad i Series 1400 HMM