Lenovo ThinkCentre A51, Quick Reference Manual

Page: 49 / 478

LED Diagnostics
Some machine types have two LEDs located on power supply on the back of
your computer. 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. The following table gives the LED diagnostics.
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
pressing the
power
button)
On Off Failing system board
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 Dos Diagnostics
The PC Doctor 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 using the Product Recovery program on your hard
disk. Alternatively, you can create bootable diagnostics diskettes from the
Product Recovery program.
You can also download the latest version of the diagnostics program from
http://www.ibm.com/pc/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
25