Solving Power Supply Problems; Testing Power Supply - HP Z238 Maintenance And Service Manual

Solving power supply problems

This section presents power supply troubleshooting scenarios.

Testing power supply

To test the power supply:
1. Unplug the AC power.
2. Unplug all power cables to the system boards.
3. Plug in AC power and verify the following:
Problem
PSU shuts down intermittently.
Workstation powers off and the
Power LED flashes red 2 times (once
every second), followed by a two-
second pause.
Power LED flashes red (once every 2
seconds).
60 Chapter 4 Diagnostics and troubleshooting
Cause
Power supply fault.
Processor thermal protection is
activated.
A fan might be blocked or not
turning.
OR
The processor heatsink fan
assembly is not properly
attached to the processor.
Power failure (power supply is
overloaded).
Solution
Replace the PSU.
1. Make sure that the workstation air vents are not
blocked.
2. Open the access panel and press the workstation power
button.
3. Verify that the system fan is running.
4. Verify that the processor heatsink fan spins.
If the heatsink fan is not spinning, verify that the fan
cable is plugged into the system board connector. Verify
that the fan is properly seated.
5. Replace the processor heatsink.
1. Determine whether a device is causing the problem by
performing the following:
a. Disconnect AC power.
b. Remove all attached devices.
c. Turn on the workstation.
If the system enters the POST, perform the following:
a. Power off the workstation.
b. Replace one device at a time and repeat this
procedure until a failure occurs.
c. Replace the device causing the failure.
d. Continue adding devices one at a time to verify
that all devices are functioning.
2. Verify power supply functionality.
a. Disconnect AC power.
b. Unplug all system board power cables.
c. Plug in AC power.
If the PSU fan spins and the LED is
●
illuminated (see
on page 60), the power supply is good.
Replace the system board.
Testing power supply