PC POST Beep Codes

Power On Self Test

The computer POST (Power On Self Test) tests a computer, to make sure that it meets the necessary system requirements before booting up.

If your PC does not even turn on (no lights, no sound, no fans running, etc.) this is not a POST problem so no beeps will be heard. This situation is likely to be a power related issue.

If your PC does power up but then fails the POST (Power On Self Test) , the computer normally returns a beep code indicating the problem that's preventing the computer from starting.

Generally, if the computer completes the POST, you will receive a single beep and the Operating system will start to load (with some BIOS manufacturers the computer may beep twice and then boot up).

AMI BIOS Beep Codes

Beep Code Meaning
one long Passed (no errors)
one short DRAM memory refresh failure
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, two short Video failure
one long, three short Base/Extended Memory failure
one long, eight short Display/Retrace Test failure

Award BIOS Beep Codes

Beep Code Meaning
one short Passed (no errors)
two short Any non-fatal error
one long, two short Video failure
one long, three short Keyboard Controller failure (applies to 286, 386 and 486)

Compaq BIOS Beep Codes

Beep Code Meaning
one short Passed (no errors)
two short General BIOS error - remedy
unknown
one short, two long Memory Module
one long, one short BIOS ROM checksum error
one long, two short Video error
7 Beeps: one long, one
short, one long, one short, pause, one long, two short
AGP Video
one long continuous tone Also Memory Module

IBM BIOS Beep Codes

Beep Code Meaning
none Power Supply or System Board failure (possible short)
one short Passed (no errors)
one short (blank screen) Video error (check cable)
one short (no boot) Floppy Drive error
two short Configuration Error (displayed on screen)
repeating short Power Supply or System Board failure
continuous Power Supply or System Board/Keyboard stuck
one long, one short System Board failure
one long, two short Video
(Mono/CGA) failure (check cable)
one long, three short Video
(EGA) failure (check cable)
three long Keyboard Card error

Phoenix BIOS Beep Codes

Beep Code Meaning
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 (followed by various combinations) First 64K RAM Chip/Data Line failure (combinations indicate which 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 Real time 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

AST Research BIOS Beep Codes

Beep Code Meaning
one short Low level processor verification test failed
two short Clearing keyboard controller buffers failed
three short Keyboard controller reset failed
four short Low level keyboard controller interface test
five short Reading data from keyboard controller failed
six short System board support chip initialisation failed
seven short Processor register read/write verify test failed
eight short CMOS timer initialisation failed
nine short ROM BIOS checksum test failed
ten short Initialise primary video
eleven short 8254 timer channel 0 test failed
twelve short 8254 timer channel 1 test failed
thirteen short 8254 timer channel 2 test failed
fourteen short CMOS power-on and time test failed
fifteen Short CMOS shutdown byte test failed
one long DMA channel 0 test failed
one long, one short DMA channel 1 test failed
one long, two short DMA page register test failed (POST 18)
one long, three short Keyboard controller interface test failed
one long, four short Memory refresh toggle test failed
one long, five short First 64 KB memory test failed
one long, six short Setup interrupt vector table failed
one
long, seven short
Video initialisation failed
one
long, eight short
Video memory test failed

Mylex BIOS Beep Codes

Beep Code Meaning
one Passed (no errors)
two Video adapter error
three Keyboard controller error
four Keyboard error
five PIC 0 error
six PIC 1 error
seven DMA page register error
eight RAM refresh error
nine RAM data error
ten RAM parity error
eleven DMA controller 0 error
twelve CMOS RAM error
thirteen DMA controller 1 error
fourteen CMOS RAM battery error
fifteen CMOS RAM checksum error
sixteen BIOS ROM checksum error

Mylex 386 BIOS Beep Codes

Beep Code Meaning
one long Passed (no errors)
two long Video adapter error
one long, one short, one
long
Keyboard controller error
one long, two short, one
long
Keyboard error
one long, three short, one
long
PIC 0 error
one long four short, one
long
PIC 1 error
one long, five short, one
long
DMA page register error
one long, six short, one
long
RAM refresh error
one long, seven short, one
long
RAM data error
one long, eight short, one
long
RAM parity error
one long, nine short, one
long
DMA controller 0 error
one long, ten short, one
long
CMOS RAM error
one long, eleven short, one
long
DMA controller 1 error
one long, twelve short, one
long
CMOS RAM battery error
one long, thirteen short,
one long
CMOS RAM checksum error
one long fourteen short,
one long
BIOS ROM checksum error

Quadtel BIOS Beep Codes

Beep Code Meaning
one short Passed (no errors)
two short CMOS IC error
one long, two short Video error
one long, three short Peripheral controller error

Macintosh Start Up Tones

Tones Meaning
Error Tone. (two sets of different tones) Problem with logic board or SCSI bus
Startup tone, drive spins, no video Problem with video controller
Powers on, no tone Logic board problem
High Tone, four higher tones Problem with SIMM

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