Advanced Troubleshooting 53
Advanced Troubleshooting
Diagnostic Lights
CAUTION: Before you begin any of the procedures in this section, follow the safety instructions
located in the Product Information Guide.
To help you troubleshoot a problem, your computer has four lights labeled "A," "B," "C," and "D" on
the back panel (see page 71). The lights can be yellow or green. When the computer starts
normally, the lights flash. After the computer starts, all four lights display solid green. If the
computer malfunctions, the color and sequence of the lights identify the problem.
Light Pattern Problem Description Suggested Resolution
The computer is in a normal off
condition or a possible pre-BIOS failure
has occurred.
Plug the computer into a working
electrical outlet and press the power
button.
A possible processor failure has occurred. Reinstall the processor (see page 103)
and restart the computer.
ABCD
ABCD
= yellow
= green
= off