(updated 12/17/2012)

Beep Codes, Simplified...

When a personal computer is first turned on, the BIOS tests and configures various components to ensure that they are operating correctly. This operation is called POST (power-on self test). If the BIOS detects any problems during this testing phase, it will attempt to continue to start the computer. However, if the problems are severe, the BIOS may be forced to halt the system.

When an error is detected, the BIOS program will:

1) Display the error to the screen, if possible.

2) Generate a POST beep code using the computer's internal speaker if it cannot access the display adaptor.

This short table explains what a few of the common beep patterns are.

Pattern of Beeps Possible Meaning
No beeps Power supply or system board problem
1 short beep Normal - Power On Self Test is okay
2 short beeps POST failed - error message on screen
Repeating short beeps Power supply, memory or system board problem
1 long, 3 short beeps Video card problem

Unfortunately, the patterns and their meanings are not uniform across all computer models. BIOS manufacturers, like Phoenix, AMI, and Award, all have their own codes. IBM, Compaq and others will also have their own codes. Other custom BIOS's will have their own codes, too.

Try websites (American Megatrends), and Award/Phoenix, for a more complete list of their beep codes and error messages. Do a search for "beep codes" and you will find many other websites with this information.


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