BEEP CODES AND ERROR MESSAGES

POST ABCs

The computer power-on self-test (POST) tests the computer to make sure it meets the necessary system requirements and that all hardware is working properly before starting the remainder of the boot process. If the computer passes the POST the computer will have a single beep (with some computer BIOS manufacturers it may beep twice) as the computer starts and the computer will continue to start normally. However, if the computer fails the POST, the computer will either not beep at all or will generate a beep code, which tells the user the source of the problem.

Beep signal	Additional indicators	Meaning
continuous beep		System board failure
one beep	unreadable, blank or flashing LCD	LCD connector problem LCD backlight inverter failure video adapter faulty LCD assembly faulty System board failure power supply failure
one beep	Message "Unable to access boot source"	Boot device failure; system board failure
one long, two short beeps		System board failure Video adapter problem LCD assembly failure
one beep, three short beeps three short beeps, one beep		Memory problem: bad DIMM or bad DIMM slot
one long, four short beeps		Low battery voltage
one beep every second		Low battery voltage
two short beeps	error codes	POST error message
two short beeps		System board failure

Additional information on the POST

AMI BIOS beep codes

Beep Code	Descriptions
1 short	DRAM refresh failure
2 short	Parity circuit failure
3 short	Base 64K RAM failure
4 short	System timer failure
5 short	Process failure
6 short	Keyboard controller Gate A20 error
7 short	Virtual mode exception error
8 short	Display memory Read/Write test failure
9 short	ROM BIOS checksum failure
10 short	CMOS shutdown Read/Write error
11 short	Cache Memory error
1 long, 3 short	Conventional/Extended memory failure
1 long, 8 short	Display/Retrace test failed

AWARD BIOS beep codes

Beep Code	Description
1 long, 2 short	Indicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information
Any other beep(s)	RAM problem.

If any other correctable hardware issues, the BIOS will display a message.

IBM BIOS beep codes

Beep Code	Description
No Beeps	No Power, Loose Card, or Short.
1 Short Beep	Normal POST, computer is ok.
2 Short Beep	POST error, review screen for error code.
Continuous Beep	No Power, Loose Card, or Short.
Repeating Short Beep	No Power, Loose Card, or Short.
One Long and one Short Beep	Motherboard issue.
One Long and Two Short Beeps	Video (Mono/CGA Display Circuitry) issue.
One Long and Three Short Beeps.	Video (EGA) Display Circuitry.
Three Long Beeps	Keyboard or Keyboard card error.
One Beep, Blank or Incorrect Display	Video Display Circuitry.

Macintosh startup tones

Tones	Error
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.