Dell Precision R5500 Owner's Manual page 64

Light Pattern
Diagnostic LEDs
64 Troubleshooting
Problem Description
Power
Button
LED
A possible system board failure
has occurred.
A possible system board, power
supply, or peripheral failure has
occurred.
Memory modules are detected,
but a memory power failure has
occurred.
A possible CPU or system board
failure has occurred.
BIOS may be corrupt or missing.
A possible system board failure
has occurred.
Power connector not installed
properly.
Possible peripheral card or
system board failure has
occurred.
A possible system board failure
has occurred.
Troubleshooting Steps
Unplug the computer. Allow one minute for the power
to drain. Plug the computer into a working electrical
outlet and press the power button.
• 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 supply button. If it illuminates,
there could be a problem with the system board.
• If the LED still does not illuminate, the problem is
with the power supply.
• If two or more memory modules are installed,
remove the modules, then re-install one module
and re-start the computer. If the computer starts
normally, continue to install additional memory
modules (one at a time) until you have identified a
faulty module or reinstalled all modules without
error. If only one memory module is installed, try
moving it to a different DIMM connector and re-
start the computer.
• If available, install verified working memory of the
same type into your computer.
Replace the CPU with a known good CPU. If the
computer still fails to boot, inspect the CPU socket for
damage.
The computer hardware is operating normally but the
BIOS may be corrupt or missing.
Remove all peripheral cards from the PCI and PCI-E
slots and re-start the computer. If the computer
boots, add the peripheral cards back one by one until
you find the bad one.
Re-seat the 2x2 power connector from the power
supply unit.
Remove all peripheral cards from the PCI and PCI-E
slots and re-start the computer. If the computer
boots, add the peripheral cards back one by one until
you find the bad one.
• Disconnect all internal and external peripherals, and
re-start the computer. If the computer boots, add
the peripheral cards back one by one until you find
the bad one.