Interpreting POST diagnostic front panel LEDs
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: 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
Activity | Beeps | Possible Cause | Recommended Action |
|
|
|
|
Green Power LED On. | None | Computer on. | None |
Green Power LED flashes | None | Computer in Suspend to |
every two seconds. |
| 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 | 2 | Processor thermal | 1. | Ensure that the computer air vents are not |
times, once every second, |
| protection activated: |
| blocked and the processor cooling fan is |
followed by a two second |
| A fan may be blocked or |
| running. |
pause. Beeps stop after fifth |
| 2. |
| |
iteration but LEDs continue |
| not turning. | Open hood, press power button, and see if | |
until problem is solved. |
| OR |
| the processor fan spins. If the processor fan |
|
|
| is not spinning, make sure the fan's cable is | |
|
| The heat sink/fan |
| plugged onto the system board header. |
|
|
|
| |
|
| assembly is not properly | 3. | If fan is plugged in, but is not spinning, then |
|
| attached to the processor. |
| replace heat sink/fan assembly. |
|
|
| 4. | Contact an authorized reseller or service |
|
|
|
| provider. |
|
|
|
|
|
Red Power LED flashes three | 3 | Processor not installed | 1. | Check to see that the processor is present. |
times, once every second, |
| (not an indicator of bad | 2. | Reseat the processor. |
followed by a two second |
| processor). |
pause. Beeps stop after fifth iteration but LEDs continue until problem is solved.
Interpreting POST diagnostic front panel LEDs 143