Lenovo 90HU, Hardware Maintenance Manual

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Chapter 4. General Checkout
Attention: The drives in the computer you are servicing might have been rearranged or the drive startup
sequence changed. Be extremely careful during write operations such as copying, saving, or formatting.
Data or programs can be overwritten if you select an incorrect drive.
General error messages appear if a problem or conflict is found by an application program, the operating
system, or both. For an explanation of these messages, refer to the information supplied with that software
package.
Use the following procedure to help determine the cause of the problem:
1. Power-off the computer and all external devices.
2. Check all cables and power cords.
3. Set all display controls to the middle position.
4. Power-on all external devices.
5. Power-on the computer.
• Look for displayed error codes
• Look for readable instructions or a main menu on the display.
If you did not receive the correct response, proceed to step 6.
If you do receive the correct response, proceed to step 7.
6. Look at the following conditions and follow the instructions:
• If the computer displays a POST error, go to “POST error codes”.
• If the computer hangs and no error is displayed, continue at step 7.
7. If the test stops and you cannot continue, replace the last device tested.
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