IBM Desktop BIOS:
| Beeps | Error Message | Description | |||
| 1 short | Normal POST | System is booting properly | |||
| 2 short | Initialization error | Error code is displayed | |||
| 1 long, 1 short | System board error | ||||
| 1 long, 2 short | Video adapter error | ||||
| 1 long, 3 short | EGA/VGA adapter error | ||||
| 3 long | 3270 keyboard adapter error | ||||
| Continuous | Power supply error | Replace the power supply | |||
| 999s | Power supply error | Replace the power supply | |||
| No beep | Power supply | Replace the power supply |