| Beeps | Fatal Failures Beep code |
|---|
| 1-1-3 | CMOS write/read (or real-time clock read/write) |
| 1-1-4 | ROM BIOS checksum |
| 1-2-1 | Programmable interval timer |
| 1-2-2 | DMA initialization |
| 1-2-3 | DMA page register write/read |
| 1-2-4 | SRAM test and configuration |
| 1-3-1 | RAM refresh verification |
| 1-3-3 | 1st 64kb RAM chip or data line failure, multibit |
| 1-3-4 | First 64K RAM odd/even logic |
| 1-4-1 | Address line failure first 64K RAM |
| 1-4-2 | Parity failure first 64K RAM2-1-1 Bit 0 first 64K RAM |
| 2-1-2 | Bit 1 first 64K RAM |
| 2-1-3 | Bit 2 first 64K RAM |
| 2-1-4 | Bit 3 first 64K RAM |
| 2-2-1 | Bit 4 first 64K RAM |
| 2-2-2 | Bit 5 first 64K RAM |
| 2-2-3 | Bit 6 first 64K RAM |
| 2-2-4 | Bit 7 first 64K RAM |
| 2-3-1 | Bit 8 first 64K RAM |
| 2-3-2 | Bit 9 first 64K RAM |
| 2-3-3 | Bit 10 first 64K RAM |
| 2-3-4 | Bit 11 first 64K RAM |
| 2-4-1 | Bit 12 first 64K RAM |
| 2-4-2 | Bit 13 first 64K RAM |
| 2-4-3 | Bit 14 first 64K RAM |
| 2-4-4 | Bit 15 first 64K RAM |
| 3-1-1 | Slave DMA register |
| 3-1-2 | Master DMA register |
| 3-1-3 | Master interrupt mask register failure |
| 3-1-4 | Slave interrupt mask register failure |
| 3-2-4 | Keyboard controller test failure |
| 3-3-4 | Screen initialization |
| 3-4-1 | Screen retrace |
| 3-4-2 | Search for video ROM in progress (not failure) |
| Beeps | Non-Fatal Failures code |
|---|
| 4-2-1 | Timer tick interrupt test (or in progress) |
| 4-2-2 | Shutdown test (or in progress) |
| 4-2-3 | Gate A20 failure |
| 4-2-4 | Unexpected interrupt in protected mode |
| 4-3-1 | RAM test in progress or address failure > FFFFh |
| 4-3-3 | Interval timer Channel 2 (or test) |
| 4-3-4 | Time-of-day clock (or test) |
| 4-4-1 | Serial port (or test) |
| 4-4-2 | Parallel port (or test) |
| 4-4-3 | Math coprocessor (or test) |
| low 1-1-2 | System-board select |
| low 1-1-3 | Extended CMOS RAM |