Interpreting Post Diagnostic Front Panel Leds And Audible Codes - HP Compaq dc7800 USDT Troubleshooting Manual

Interpreting POST Diagnostic Front Panel LEDs and
Audible Codes
This section covers the front panel LED 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.
WARNING!
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 wall outlet and allow the internal system components to cool
before touching.
NOTE: If you see flashing LEDs on a PS/2 keyboard, look for flashing LEDs on the front panel of the
computer and refer to the following table to determine the front panel LED 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 A-2 Diagnostic Front Panel LEDs and Audible Codes
Activity
Green Power LED On.
Green Power LED flashes
every two seconds.
Red Power LED flashes two
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 three
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 four
times, once every second,
followed by a two second
pause. Beeps stop after fifth
iteration but LEDs continue
until problem is solved.
ENWW
When the computer is plugged into an AC power source, voltage is always applied to the
Beeps
None
None
2
3
4

Interpreting POST Diagnostic Front Panel LEDs and Audible Codes

Possible Cause
Computer on.
Computer in Suspend to
RAM mode (some models
only) or normal Suspend
mode.
Processor thermal
protection activated:
A fan may be blocked or
not turning.
OR
The heatsink/fan
assembly is not properly
attached to the processor.
Processor not installed
(not an indicator of bad
processor).
Power failure (power
supply is overloaded).
OR
The incorrect external
power supply adapter is
being used on the USDT.
Recommended Action
None
None required. Press any key or move the mouse
to wake the computer.
1. Ensure that the computer air vents are not
blocked and the processor cooling fan is
running.
2. Open hood, press power button, and see if
the processor 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 heatsink/fan assembly.
4. Contact an authorized reseller or service
provider.
1. Check to see that the processor is present.
2. Reseat the processor.
1. Open the hood and ensure the 4 or 6-wire
power supply cable is seated into the
connector on the system board.
2. Check if a device is causing the problem by
removing ALL attached devices (such as
hard, diskette, or optical drives, and
expansion cards). 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.
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