Dell Precision R5500 - Page 78

Light Pattern
Problem Description Troubleshooting
Steps
Diagnostic LEDs Power Button LED
working electrical
outlet and press the
power button.
A possible system
board, power
supply, or peripheral
failure has
occurred.
• Power off
computer,
leaving the
computer
plugged in.
Press and hold
the power
supply test
button at the
rear of the
power supply
unit. If the LED
next to the
switch
illuminates, the
problem may be
with your
system board.
• If the LED next
to the switch
does not
illuminate,
disconnect all
internal and
external
peripherals, and
press and hold
the power
supply test
button. If it
illuminates,
there could be a
problem with a
peripheral.
• If the LED still
does not
illuminate,
remove the PSU
connections
from the system
board, then
press and hold
the power
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