Acer Aspire 2420, Service Manual

Page: 109 / 170

Chapter 4 99
K External keyboard
If any of these devices do not work, reconnect the cable connector and repeat the failing operation.
Memory check
Memory errors might stop system operations, show error messages on the screen, or hang the system.
1. Boot from the diagnostics diskette and start the doagmpstotics program (please refer to main board.
2. Go to the diagnostic memory in the test items.
3. Press F2 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 Check
To 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 by
the battery pack.
If you suspect a power problem, see the appropriate power supply check in the following list:
K “Check the Power Adapter” on page 100
K “Check the Battery Pack” on page 101