HP ProDesk 400 G1 Maintenance And Service Manual page 212

Activity
Red Power LED flashes eleven
times, once every second,
followed by a two second
pause. Beeps stop after fifth
iteration but LEDs continue until
problem is solved.
System does not power on and
LEDs are not flashing.
202 Chapter 9 POST error messages
Beeps Possible cause
11 The current processor does
not support a feature
previously enabled on this
system.
None System unable to power
on.
Recommended action
1.
Reinstall the original processor.
Press and hold the power button for less than 4
seconds. If the hard drive LED turns white, the
power button is working correctly. Try the
following:
1.
Check that the voltage selector (some
models), located on the rear of the power
supply, is set to the appropriate voltage.
Proper voltage setting depends on your
region.
2. 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
white 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. If the
problem persists, replace the system board.
5. If the 5V_aux light on the system board is
not turned on, remove the expansion cards
one at a time until the 5V_aux light on the
system board turns on. It the problem
persists, replace the power supply.