Interpreting Post Diagnostic Front Panel Lights And Audible Codes - HP EliteDesk 705 G5 Maintenance And Service Manual

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:
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
White power light On.
White power light flashes every
two seconds.
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.
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.
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.
104 Chapter 7 POST error messages
When the computer is plugged into an AC power source, voltage is always applied to the system
Beeps
None
None
2
4
5
Possible cause Recommended action
Computer on. None
Computer in Suspend to None required. Press any key or move the mouse to
RAM mode (some models wake the computer.
only) or normal Suspend
mode.
Processor thermal 1.
protection activated:
A fan may be blocked or not 2.
turning.
OR
The heat sink/fan assembly
3.
is not properly attached to
the processor.
4.
Power failure (power supply 1.
is overloaded).
2.
3.
Pre-video memory error. CAUTION:
system board, you must unplug the computer power
cord before attempting to reseat, install, or remove a
DIMM module.
1.
2.
3.
Ensure that the computer air vents are not
blocked and the cooling fan is running.
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.
If fan is plugged in, but is not spinning, then
replace fan.
Contact an authorized reseller or service
provider.
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.
Replace the power supply.
Replace the system board.
To avoid damage to the DIMMs or the
Reseat DIMMs.
Replace DIMMs one at a time to isolate the
faulty module.
Replace third-party memory with HP memory.