Interpreting POST diagnostic front panel lights and
audible codes
This section covers the front panel light codes as well as the audible codes that may occur before or during
POST that do not necessarily have an error code or text message associated with them.
CAUTION:
When the computer is plugged into an AC power source, voltage is always applied to the system
board. To reduce the risk of personal injury from electrical shock and/or hot surfaces, be sure to disconnect
the power cord from the AC outlet and allow the internal system components to cool before touching.
NOTE:
If you see flashing lights on a PS/2 keyboard, look for flashing lights on the front panel of the
computer and see the following table to determine the front panel light codes.
Recommended actions in the following table are listed in the order in which they should be performed.
Not all diagnostic lights and audible codes are available on all models.
Table 7-1
Interpreting POST diagnostic front panel lights and audible codes
Activity
Beeps
Possible cause
Recommended action
White power light On.
None
Computer on.
None
White power light flashes every
two seconds.
None
Computer in Suspend to
RAM mode (some models
only) or normal Suspend
mode.
None required. Press any key or move the mouse to
wake the computer.
Red power light flashes two
times, once every second,
followed by a two second pause.
Beeps stop after fifth iteration
but lights continue until problem
is solved.
2
Processor thermal
protection activated:
A fan may be blocked or not
turning.
OR
The heat sink/fan assembly
is not properly attached to
the processor.
1.
Ensure that the computer air vents are not
blocked and the cooling fan is running.
2.
Open hood, press power button, and see if the
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 fan.
4.
Contact an authorized reseller or service
provider.
Red power light flashes four
times, once every second,
followed by a two second pause.
Beeps stop after fifth iteration
but lights continue until problem
is solved.
4
Power failure (power supply
is overloaded).
1.
Check if a device is causing the problem by
removing all attached devices. 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.
Red power light flashes five
times, once every second,
followed by a two second pause.
Beeps stop after fifth iteration
but lights continue until problem
is solved.
5
Pre-video memory error.
CAUTION:
To avoid damage to the DIMMs or the
system board, you must unplug the computer power
cord before attempting to reseat, install, or remove a
DIMM module.
1.
Reseat DIMMs.
2.
Replace DIMMs one at a time to isolate the
faulty module.
3.
Replace third-party memory with HP memory.
104 Chapter 7 POST error messages
