HP mt20 Maintenance And Service Manual page 86

Table 9-3 Diagnostic front panel LEDs and audible codes (continued)
Activity
Beeps stop after fifth iteration
but LEDs continue until problem
is solved.
Red Power LED flashes five
times, once every second,
followed by a two second pause.
Beeps stop after fifth iteration
but LEDs continue until problem
is solved.
Red Power LED flashes six times,
once every second, followed by a
two second pause. Beeps stop
after fifth iteration but LEDs
continue until problem is solved.
Red Power LED flashes eight
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.
76 Chapter 9 Diagnostics and troubleshooting
Beeps Possible Cause
The incorrect external
power supply adapter is
being used on the unit.
5 Pre-video memory error.
6 Pre-video graphics error.
8 Invalid ROM based on bad
checksum.
None System unable to power on.
Recommended Action
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.
CAUTION: To avoid damage to the memory
modules or the system board, you must unplug the
computer power cord before attempting to reseat,
install, or remove a memory module.
1. Reseat memory modules.
2. Replace memory modules one at a time to
isolate the faulty module.
3. Replace third-party memory with HP memory.
4. Replace the system board.
For systems with a graphics card:
1. Reseat the graphics card.
2. Replace the graphics card.
3. Replace the system board.
For systems with integrated graphics, replace the
system board.
1. Reflash the system ROM with the latest BIOS
image using the BIOS Recovery procedure.
2. Replace the system board.
Press and hold the power button for less than four
seconds. If the hard drive LED turns white, the power
button is working correctly. Try the following:
1. Remove the power cord from the computer.
2. Open the computer and press the yellow CMOS
button on the system board for four seconds
(located near the front USB ports).
3. Verify that the AC cord is plugged into the
power supply.
4. Close the unit and reattach the power cord.
5. Try to power on the computer.
6. Replace the unit.