Power supply and system board Diagnostic LEDs

You computer has two LEDs located on power supply on the back of the chassis. The power button LED located on front of your computer and the two LEDs on the back will help you determine if the power supply or system board is working correctly. The following table uses the LEDs to diagnose possible power supply and system board problems.

Power Button

 

 

 

LED

Green LED

Yellow LED

Diagnosis

 

 

 

 

Off

Off

Off

Check the following first:

 

 

 

v Is power cord plugged in?

 

 

 

v Is the power strip on?

 

 

 

Failing power supply

 

 

 

 

Off (After

On

Off

Failing system board

pressing the

 

 

 

power

 

 

 

button)

 

 

 

 

 

 

 

On

On

On

Failing power supply

 

 

 

 

On

On

Off

Normal working conditions, but if your

 

 

 

computer is not working correctly then you

 

 

 

have a failing system board or a failing

 

 

 

microprocessor

 

 

 

 

If you cannot correct the problem, have your computer serviced.

Note: To reset the computer once a yellow LED is on, unplug the power cord.

PC-Doctor for DOS Diagnostics

The PC-Doctor for DOS Diagnostics program runs independently of the operating system. You can use this program to test hardware components of your computer. You can use this program when other methods are not available or have not been successful in isolating a possible hardware problem.

You can run the diagnostics from the Rescue and Recovery workspace on your hard disk. Alternatively, you can create bootable diagnostics diskettes from the Rescue and Recovery workspace.

You can also download the latest version of the diagnostics program from http://www.lenovo.com/think/support/ on the World Wide Web. Type your machine type and model number into the Quick Path field to find the downloadable files that are specific to your computer.

Chapter 5. Troubleshooting and diagnostics

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Lenovo 8124, 8131, 8138, 8123, 8137, TC A51-8122 Power supply and system board Diagnostic LEDs, PC-Doctor for DOS Diagnostics