BIOS Beep Codes

Written By:
Dave Kelsey
Last Edited:

If your system will not boot up and is sounding a series of BIOS beep codes, the following information may help you determine what the problem is. The first thing you need to do is count the number of beeps you hear when powering up.

POST BIOS Beep Codes:

1 short - DRAM refresh failure
2 short - Memory parity error
3 short - Base 64K memory failure
4 short - System timer failure
5 short - Processor error
6 short - Gate A20 failure
7 short - Virtual mode processor exception error
8 short - Display memory read/write error
9 short - ROM checksum error
10 short - CMOS shutdown register read/write error
11 short - Cache error
1 long, 2 short - Failure in video system
1 long, 3 short - Memory test failure
1 long, 8 short - Display test failure
2 short - POST failure
1 long - POST has passed all tests

Troubleshooting POST BIOS Beep Codes:

1 short - The programmable interrupt timer or programmable interrupt controller has probably failed.
2 short - A memory parity error has occurred in the first 64K of RAM. Reseat the memory, or replace with known good modules.
3 short - A memory failure has occurred in the first 64K of RAM. The RAM IC is probably bad, replace with known good modules.
4 short - The system clock/timer IC has failed or there is a memory error in the first bank of memory.
5 short - The system CPU has failed.
6 short - The keyboard controller IC has failed, which is not allowing Gate A20 to switch the processor to protected mode. Replace the keyboard controller.
7 short - The CPU has generated an exception error because of a fault in the CPU or motherboard circuitry.
8 short - The system video adapter is missing or defective.
9 short - The contents of the system BIOS ROM does not match the expected checksum value. The BIOS ROM is probably defective and should be replaced.
10 short - The shutdown for the CMOS has failed.
11 short - The L2 cache is faulty.
1 long, 2 short - An error was encountered in the video BIOS ROM, or a horizontal retrace failure has been encountered.
1 long, 3 short - A fault has been detected in memory above 64KB.
2 short - One of the hardware tests have failed.

Sometimes a bad add-in card can cause problems. If beep codes are not generated when all other expansion cards are absent, one of the add-in cards is causing the malfunction. Insert the cards back into the system one at a time until the problem happens again. This will reveal the malfunctioning card.

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