Problem Determination Tips - Lenovo ThinkCentre M90 Hardware Maintenance Manual

• If the LED is not illuminated (off), go to step 2 on page 32
2. Check the status of the power indicator LED on the AC/DC power adapter.
• If the LED is illuminated (on), go to step 7 on page 32.
• If the LED is not illuminated (off), go to the next step 3 on page 32.
3. Verify that the power cord is properly connected to an AC power outlet.
4. Verify that you are using a good AC power outlet. Plug another device into the outlet or contact the
power company or supplier to verify that the outlet is working correctly .
5. Check the power cord continuity.
6. Replace the AC/DC power adapter.
7. Verify that the power cord from the AC/DC power adapter to the computer is properly connected. See
"Locating connectors on the rear of your computer" on page 67.
8. Open the cover. See "Opening the computer cover" on page 70.
9. Check the power switch/LED assembly connector on the system board. See "Locating parts on the
system board" on page 69. Reseat the cable from the power switch/LED assembly to the system board.
10. Replace the power switch/LED assembly.
11. Replace the system board. See "Replacing the system board" on page 78.

Problem determination tips

Due to the variety of hardware and software combinations that can be encountered, use the following
information to assist you in problem determination. If possible, have this information available when
requesting assistance from Service Support and Engineering functions.
• Machine type and model
• Processor or hard disk drive upgrades
• Failure symptom
– Do diagnostics indicate a failure?
– What, when, where, single, or multiple systems?
– Is the failure repeatable?
– Has this configuration ever worked?
– If it has been working, what changes were made prior to it failing?
– Is this the original reported failure?
• Diagnostics version
– Type and version level
• Hardware configuration
– Print (print screen) configuration currently in use
– BIOS level
• Operating system software
– Type and version level
Notes: To eliminate confusion, identical systems are considered identical only if they:
1. Are the exact machine type and models
2. Have the same BIOS level
3. Have the same adapters/attachments in the same locations
4. Have the same address jumpers/terminators/cabling
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ThinkCentre Hardware Maintenance Manual