Diagnostic Lights
CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.
To help you troubleshoot a problem, your computer has four lights labeled "1," "2," "3," and "4" on the front or back panel. The lights can be "off" or green. When the computer starts normally, the patterns or codes on the lights change as the boot process completes. If the POST portion of system boot completes successfully, all four lights display solid green for a short time, and then turn off.
If the computer malfunctions during the POST process, the pattern displayed on the LEDs may help identify where in the process the computer halted. If the computer malfunctions after a successful POST, the diagnostic lights do not indicate the cause of the problem.
NOTE: The orientation of the diagnostic lights may vary depending on the system type. The diagnostic lights can be either vertically or horizontally oriented.
Light Pattern | Problem Description | Suggested Resolution |
The computer is in a normal "off" condition, or a possible
The diagnostic lights are not lit after the computer successfully boots to the operating system.
Plug the computer into a working electrical outlet and press the power button.
A possible BIOS failure has occurred; the computer is in recovery mode.
Run the BIOS Recovery utility, wait for recovery completion, and then restart the computer.
A possible processor failure has occurred. Reinstall the processor and restart the computer. For information on reinstalling the processor, see your online User’s Guide.
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