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: 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 |
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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 | Thermal protection | 1. | Clean the air vents on the front, back, or |
times, once every second, |
| activated: |
| any other vented side of the computer. |
followed by a two second |
| Air flow is restricted, a fan | 2. | Ensure that there is a 10.2 cm (4 in) |
pause. Beeps stop after fifth |
| |||
iteration but LEDs continue |
| may not be functioning, or |
| clearance on all vented sides of the |
until problem is solved. |
| the heatsink is not |
| computer to permit the required airflow. |
|
| properly attached. | 3. | Ensure that computers are not so near |
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| ||
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| each other that they are subject to each |
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| other's |
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| 4. | If the computer is within an enclosure, |
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|
|
| ensure that there is proper intake and |
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|
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| exhaust ventilation for the enclosure. |
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| 5. | If a message appears on the screen |
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| indicating that a fan is not working, replace |
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|
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| the fan. |
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| 6. | Ensure that the heat sink is properly |
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| attached. |
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|
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.
82 Appendix A POST Error Messages