Dell Precision T7400 (Late 2007) - Manual (Page 105)

Troubleshooting Tools 105
10
Troubleshooting Tools
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. The lights can be "off" or green. When the
computer starts normally, the lights flash. If the computer malfunctions, the
pattern of the lights and also that of the power button help to identify the
problem. These lights also indicate sleep states.
Diagnostic Light Codes Before POST
Diagnostic Lights Power
Light Problem Description Suggested Resolution
off The computer is in a
normal off condition
or in Windows
Hibernation mode.
Press the power button to
turn the computer on.
If the computer does not
turn on, ensure that the
front-panel power light is
on. If the power light is off,
ensure that the computer is
connected to a working
electrical outlet and then
press the power button.
If the problem is still not
resolved, contact Dell for
technical assistance (see
"Contacting Dell" on
page 287).