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Computer Beeps (IBM BIOS, AWARD BIOS, AMI BIOS, Phoenix BIOS)

Each time the computer is turned on, the self-test diagnostic program automatically starts when the POST (Power-On-Self-Test) is turned on, which is "written" to the BIOS ROM.

POST checks all the most important components of the computer: it monitors the performance of the processor, CMOS, supporting motherboard chips, and also conducts a quick test of RAM. Information on how the computer’s diagnostics went is issued to the computer speaker in the form of a special sound signal.

If the computer is operating normally, that is, the POST diagnostic program has completed successfully, you will hear one short beep, and then the computer’s operating system will start loading.

When an inoperative component of a computer is detected, the POST diagnostic program emits a special sound signal (a sequence of short and long beeps) that characterizes the detected error, and the computer stops its work.

If the computer issued a sequence of short and long beeps and stopped working, you need to count the number of beeps for their subsequent analysis. You can turn off the computer, wait about 30 seconds, and turn it on again. After counting the beeps, find your combination of sound signals in the table corresponding to the BIOS of your computer. In the tables that are given on this page, you will find a transcript of audio signals. Thus, even without special diagnostic tools, it is possible to localize the malfunction of a personal computer.

Since the contents of the IBM BIOS ROM were copyrighted (that is, it could not be copied to other companies), most other computer manufacturers were forced to use third-party BIOS ROMs. The BIOS of these independent companies was almost completely compatible with the IBM BIOS, however, the sound coding of the POST diagnostic program for each independent BIOS manufacturer is different from the coding of the sound signals of the IBM BIOS.

Table 1. Meaning of the sound signals of the IBM BIOS

Sound Type Sound value
One short Normal post completion, everything is OK
Absent The power supply is defective
Continuous The power supply is defective
Repeating short The power supply is defective
One long and one short Motherboard defective
One signal and blank screen Faulty video system
One long and two short Faulty video system (Mono / CGA)
One long and three short Faulty video system (EGA / VGA)
Two short Faulty video system (monitor not connected)
Three long The motherboard is faulty (keyboard controller error)

Table 2. Meaning of AWARD BIOS Beeps

Sound Type Sound value
One short Normal post completion, everything is OK
Absent The power supply is defective
One signal and blank screen Faulty video system
One long and two short Faulty video system
One long and three short Monitor not connected
Two short Any minor error
Three long The motherboard is faulty (keyboard controller error)

Table 3. Meaning of AMI BIOS Beeps

Sound Type Sound value
One short Normal post completion, everything is OK
Two short RAM test error
Three short RAM test error
Four short The motherboard is faulty (system timer error)
Five short Processor defective
Six short The motherboard is faulty (keyboard controller error)
Seven short The motherboard is faulty (virtual mode error)
Eight short Video adapter defective or video test error
Nine short BIOS ROM checksum error
Ten short CMOS write / read error
Eleven short The motherboard is faulty (cache test error)
One long and three short The motherboard is faulty (extended memory error)
One long and eight short Monitor test error

Table 4. Phoenix BIOS Beep Value

Sound Type Sound value
1 - 1 - 3 CMOS write / read error
1 - 1 - 4 BIOS ROM checksum error
1 - 2 - 1 The motherboard is faulty (system timer error)
1 - 2 - x Motherboard defective
1 - 3 - x Motherboard defective
1 - 4 - 1 Motherboard defective
1 - 4 - 2 RAM test error
1 - 4 - 3 The motherboard is faulty (system timer error)
1 - 4 - 4 Error accessing port
2 - x - x RAM test error (any combination starting with two beeps)
3 - 1 - x RAM test error
3 - 1 - 4 Motherboard defective
3 - 2 - 4 Keyboard controller defective
3 - 3 - 4 Video adapter defective or video test error
3 - 4 - x Faulty video system
4 - 2 - x Motherboard defective
4 - 3 - x Motherboard defective
4 - 3 - 4 The motherboard is faulty (real time clock error)
4 - 4 - 1 Serial port test error
4 - 4 - 2 Parallel Port Test Error
4 - 4 - 3 Math coprocessor test error


Note: x is any number from 1 to 4 if such a combination of numbers is not explicitly available.

Do not take this information as absolutely reliable. The sound coding may change as new BIOS versions become available. In addition, it should be borne in mind that audio signals facilitate the preliminary localization of a faulty component, indicating the correct direction for further diagnosis of a computer malfunction.