HP Dc7700 HP Compaq dc7700 Business Desktop PC Service Reference Guide, 1st Ed - Page 222

Troubleshooting Without Diagnostics Solving Minor Problems (Continued) Problem Cause 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. Processor thermal protection activated: A fan may be blocked or not turning. OR The heatsink is not properly attached to the processor. System does not power on and the LEDs on the front of the computer are not flashing. System unable to power on. Possible Solution 1. Ensure computer air vents are not blocked and the cooling fan is running. 2. Open hood, press power button, and see if the processor fan spins. If not spinning, make sure the fan's cable is plugged onto the system board header. 3. Replace the processor heatsink-fan assembly. Press and hold the power button for less than 4 seconds. If the hard drive LED turns green, then: 1. Check that the voltage selector, located on the rear of the power supply on some models, is set to the appropriate voltage. 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 seconds. The hard drive LED does not turn on green. 1. Check that the unit is plugged into a working AC outlet. 2. Open hood and check that the power button harness is properly connected to the system board. 3. Check that both 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, then replace the power button harness. 5. If the 5V_aux light on the system board is off, then replace the power supply. 6. Replace the system board. D-4 433612-001 Service Reference Guide, dc7700