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!
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 wall outlet and allow the internal system components to
cool before touching.
NOTE:
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 5-3
Diagnostic Front Panel LEDs and Audible Codes
Activity
Beeps
Possible Cause
Recommended Action
Green Power LED On.
None
Computer on.
None
Green Power LED 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 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.
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.
OR
The unit has vents
blocked or is in a location
where the ambient
temperature is too high.
1.
Ensure that the computer air vents are not
blocked and the processor cooling fan is
plugged in and running, if equipped.
2.
Contact an authorized reseller or service
provider.
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.
4
Power failure (power
supply is overloaded).
OR
The incorrect external
power supply adapter is
being used on the unit.
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.
Interpreting POST Diagnostic Front Panel LEDs and Audible Codes
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