BIOS Beep Codes

Computer POST

At startup computers run through a pre-boot check list of items to ensure everything is hunky dory with the attached hardware components. The process is known as POSTing. POST is an acronym for Power On Self Test.

A fully functional computer will normally give a single beep at bootup. The single beep indicates everything is okay and will continue with the boot process and load the operating system.

If the computer gives any other beeps or no beeps, you have a problem.

Common BIOS systems beep codes:

AMI (American Megatrends') BIOS
Beep Codes
one short DRAM refresh failure (Problem with memory)
two short Parity circuit failure
three short Base 64K RAM failure
four short System Timer failure
five short Processor failure
six short Keyboard Controller / Gate A20 failure
seven short Virtual Mode Exception error
eight short Display Memory Read/Write failure (fault with video card)
nine short ROM BIOS Checksum error (fault with BIOS chip)
ten short CMOS Shutdown Read/Write error
eleven short Cache memory
one long Passed (no errors)
one long, two short Video failure
one long, three short Base / Extended Memory failure
one long, eight short Display / Retrace Test failure

Phoenix BIOS
Beep Codes
one, one, three CMOS Read/Write
one, one, four ROM BIOS Checksum failure
one, two, one Programmable Interval Timer failure
one, two, two DMA Initialisation failure
one, two, three DMA Page Register Read/Write failure
one, three, one RAM Refresh Verification error
one, three, three First 64K RAM Chip/Data Line failure
one, three, four First 64K RAM Odd/Even Logic
one, four, one First 64K RAM: Address Line
one, four, two First 64K RAM: Parity failure
one, four, three Fail-Safe Timer Feature (EISA only)
one, four, four Software NMI Port failure (EISA only)
two (plus combo) First 64K RAM Chipfailure (combo indicates bit)
three, one, one Slave DMA Register failure
three, one, two Master DMA Register failure
three, one, three Master Interrupt Mask Register failure
three, one, four Slave Interrupt Mask Register failure
three, two, four Keyboard Controller failure
three, three, four Display Memory failure
three, four, one Display Retrace failure
three, four, two Video ROM search proceeding
four, two, one Timer Tick failure
four, two, two Shutdown failure
four, two, three Gate A20 failure
four, two, four Unexpected Interrupt in Protected Mode
four, three, one RAM test above 64K failure
four, three, two/three Programmable Interval Timer, Channel 2 failure
four, three, four Realtime Clock failure
four, four, one Serial Port error
four, four, two Parallel Port error
four, four, three Math Co-processor failure
(tone) one, one, two System Board Select
(tone) one, one, three Extender CMOS RAM

Check the series of beeps (or lack of) against the tables and its a starting point for troubleshooting your system.

That's about it.