Solving Power Supply Problems - HP Compaq Businessdc7600 Service & Reference Manual

Solving Power Supply Problems

Solving Power Supply Problems
Problem
Power supply shuts down
intermittently.
Computer powered off
automatically and the
Power LED flashes Red two
times, once every second,
followed by a two second
pause, and the computer
beeps two times. Beeps
continue for five iterations
after which the LED flashes
will continue until the
problem is resolved.
Power LED flashes Red, four
times, once every second,
followed by a two second
pause, and the computer
beeps four times. Beeps
continue for five iterations
after which the LED flashes
will continue until the
problem is resolved.
Service Reference Guide, dc7600
Cause
Voltage selector switch
on rear of computer
chassis (some models) is
not switched to correct
line voltage.
Power supply fault.
Processor thermal
protection activated:
A fan may be blocked
or not turning.
OR
The heatsink/fan
assembly is not properly
attached to the
processor.
Power failure (power
supply is overloaded).
390742-001
Troubleshooting Without Diagnostics
Solution
Select the proper AC voltage.
Replace the power supply.
1. Ensure that the computer air
vents are not blocked and the
cooling fan is running.
2. Open hood, press the power
button, and see if the processor
fan spins. If the processor fan is
not spinning, make sure the
fan's cable is plugged onto the
system board header. Ensure
the fan is fully/properly seated
or installed.
3. If the fan is pugged in and
seated but not spinning, replace
the processor fan.
4. Reseat processor heatsink and
verify that the fan assembly is
properly attached.
1. Check that the voltage selector
(some models), is set to the
appropriate voltage.
2. Open the hood and ensure the
4- or 6-wire power supply cable
is seated into the connector on
the system board.
3. Check if a device is causing the
problem by removing ALL
attached devices. Power on the
system. If the system enters the
POST, then power off and
replace one device at a time
and repeat this procedure until
failure occurs. Replace the
device causing the failure.
Continue adding devices one at
a time to ensure all devices are
functioning properly.
4. Replace the power supply.
5. Replace the system board.
D–5