Dell Precision Guide De Configuration Et De Référence Rapide page 46

46
Setup and Quick Re ference Guide
Diagnostic Lights
When you turn on your computer, it performs a series of self-diagnostic
tests. A successful power-on self-test (POST) ends with a single beep that
signifies the start of normal operation. If the computer fails to complete the
POST, a series of lights located on the computer can help you understand
which test failed or why the computer stopped responding. These lights
communicate problems encountered before and during POST only, not
during normal operation. To locate the diagnostic lights, see "Back Panel" on
page 46.
The following table lists the code for the diagnostic lights, gives probable
causes, and suggests corrective actions.The lights are labeled to help you
match the pattern on your computer with ones shown in the table.
B a c k P a n e l
diagnostic lights
D i a g n o s t i c L i g h t C o d e s D u r i n g P O S T
Light Pattern
A
off
B
off
C
off
D
off
= y e l l o w
= g r e e n
= o f f
Cause
No electrical power is supplied to the computer.