Troubleshooting Guide
A–10 www.hp.com Troubleshooting Guide
POST Error Messages
System does not 
power on and LEDs 
are not flashing.
None System unable 
to power on.
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, 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. If the hard drive LED 
does not turn on green then:
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 not turned on, then 
replace the power supply.
6. Replace the system board.
Diagnostic Front Panel LEDs and Audible Codes (Continued)
Activity Beeps
Possible 
Cause Recommended Action










