Solving Power Problems - HP Compaq Pro 4300 Maintenance & Serice Manual

Solving Power Problems

Common causes and solutions for power problems are listed in the following table.
Table 7-2 Solving Power Problems
Power supply shuts down intermittently.
Cause
If equipped with a voltage selector, voltage selector switch
on rear of computer chassis (some models) not switched to
correct line voltage (115V or 230V).
Power supply will not turn on because of internal power
supply fault.
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 stop after fifth iteration but LEDs continue flashing.)
Cause
Processor thermal protection activated:
A fan may be blocked or not turning.
OR
The heat sink is not properly attached to the processor.
98 Chapter 7 Troubleshooting Without Diagnostics
Solution
Select the proper AC voltage using the selector switch.
Replace the power supply.
Solution
1. Ensure that the computer air vents are not blocked and
the processor cooling fan is running.
2. Open the access panel, press the power button, and
see if the processor fan (or other system fan) spins. If
the fan does not spin, make sure the fan cable is
plugged onto the system board header.
3. If fan a plugged in and not spinning, replace it.