Dell U7021, WHL Diagnostic Lights, Electrical outlet and press the power, Has occurred Button

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	Plug the computer into a working
		condition or a possible pre-BIOS failure	electrical outlet and press the power
A B C	D	has occurred.	button.

A possible processor failure has occurred. Reinstall the processor (see page 103) and restart the computer.

A B C D

= yellow = green = off

Advanced Troubleshooting

53