Dell Precision R5500 (Early 2011) - Manual (Page 76)

Light Pattern Problem Description Troubleshooting Steps
Diagnostic LEDs Power Button LED
computer turns on
properly.
• Ensure that any
power strips being
used are plugged
into an electrical
outlet and are
turned on.
• Ensure that the
electrical outlet is
working by testing it
with another
device, such as a
lamp.
• Ensure that the
main power cable
and front panel
cable are securely
connected to the
system board.
A possible system board
failure has occurred. Unplug the computer. Allow
one minute for the power to
drain. Plug the computer
into a 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
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