HP (Hewlett-Packard) SM774UP Personal Computer User Manual


 
Solving Power Problems
Common causes and solutions for power problems are listed in the following table.
Table C-2 Solving Power Problems
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 Solution
Processor thermal protection activated:
A fan may be blocked or not turning.
OR
The heat sink is not properly attached to the processor.
1. Ensure that the computer air vents are not blocked and
the processor cooling fan is running.
2. Open hood, press 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.
3. If fan is plugged in, but is not spinning, then replace the
heat sink/fan assembly.
Power LED flashes red four times, once every second, followed by a two second pause, and the computer beeps
four times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause Solution
Power failure (power supply is overloaded). 1. Check if a device is causing the problem by removing
ALL attached devices (such as hard, diskette, or optical
drives, and expansion cards). 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 that is causing
the failure. Continue adding devices one at a time to
ensure all devices are functioning properly.
2. Replace the power supply.
3. Replace the system board.
Solving Power Problems 101