1 short beep
Normal POST—the system is OK.
2 short beeps
POST error—error code shown on screen.
No beep
Power supply or motherboard problem (use a multimeter to check the onboard speaker is functioning).
Continuous beep
Power supply, motherboard, or system memory problem.
Repeating short beeps
Power supply, motherboard, or keyboard problem.
1 long, and then 1 short beep
Motherboard problem.
1 long, and then 2 or 3 short beeps
Display adapter error.
3 long beeps
3270 keyboard card.