Diagnostic Lights - Dell OptiPlex 740 Quick Reference Manual

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 "1," "2," "3," and "4" on the
front 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. If the computer malfunctions during the POST process,
the pattern displayed on the LEDs may help identify where in the process the computer halted.
NOTE:
The orientation of the diagnostic lights may vary depending on the system type. The diagnostic lights can
appear either vertical or horizontal.
Light Pattern Problem Description
The computer is in a normal off condition,
or a possible pre-BIOS failure has
occurred.
The diagnostic lights are not lit after the
computer successfully boots to the
operating system.
A possible BIOS failure has occurred; the
computer is in the recovery mode.
A possible processor failure has occurred.
Memory modules are detected, but a
memory failure has occurred.
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Quick Reference Guide
Suggested Resolution
Plug the computer into a working
electrical outlet and press the power
button.
Run the BIOS Recovery utility, wait for
recovery completion, and then restart the
computer.
Reinstall the processor and restart the
computer.
• If you have one memory module
installed, reinstall it and restart the
computer (see the online User's Guide
for instructions on how to remove and
install memory modules).
• If you have two or more memory
modules installed, remove the modules,
reinstall one module, and then restart
the computer. If the computer starts
normally, reinstall an additional module.
Continue until you have identified a
faulty module or reinstalled all modules
without error.
• If available, install properly working
memory of the same type into your
computer.
• If the problem persists, contact Dell.