Solving Power Problems; Power Supply Shuts Down Intermittently - HP Z Series Maintenance And Service Manual

Cause
System unable to power on.

Solving power problems

These tables provide common causes and solutions for power problems.

Power supply shuts down intermittently

Use this information to troubleshoot the computer.
Cause
If the computer has a voltage selector, the
voltage selector switch on the rear of the
computer chassis (select products only) is not
switched to the correct line voltage (115 V or
230 V).
Power supply will not turn on because of
internal power supply fault.
Computer turned off automatically, power light blinks red two times followed by
a two-second pause, and the computer beeps two times (beeps stop after fifth
iteration but lights continue blinking)
Use this information to troubleshoot the computer.
40 Chapter 5 Troubleshooting without diagnostics
Solution
Press and hold the power button for fewer than 4 s. If the hard drive light
turns white:
1. If the computer has a voltage selector, check that the voltage
selector (located on the rear of the power supply) is set to the
appropriate voltage. The proper voltage setting depends on your
region.
2. Remove the expansion cards one at a time until the 5V_aux light on
the system board turns on.
3. Replace the system board.
OR
Press and hold the power button for less than 4 s. If the hard drive light
does not turn white:
1. Check whether the unit is plugged into a working AC outlet.
2. Open the access panel and check that the power button cable is
properly connected to the system board.
3. Check that the power supply cables are properly connected to the
system board.
4. Check to see if the 5V_aux light on the system board is turned on. If
it is turned on, replace the power button assembly.
5. If the 5V_aux light on the system board is off, replace the power
supply.
6. Replace the system board.
Solution
Select the proper AC voltage using the selector switch.
Replace the power supply.