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Advanced Troubleshooting 39
Advanced Troubleshooting
Diagnostic Lights
To help you troubleshoot a problem, your computer is equipped with four lights on the back panel
labeled "A," "B," "C," and "D" (see page 39). These lights can be yellow or green. When the
computer starts normally, the lights flash. After the computer starts, the lights remain green. If the
computer malfunctions, the color and sequence of the lights identify the problem.
CAUTION: Before you begin any of the procedures in this section, follow the safety instructions
located in the Product Information Guide.
Light Pattern Problem Description Suggested Resolution
The computer is in a normal off
condition or a possible pre-BIOS
failure has occurred.
Verify that the computer is plugged
into a working electrical outlet and
that you have pressed the power
button.
A B C D
= yellow
= green
= off