Introduction
Have you ever pressed the power button on your computer, only to be greeted by a completely black screen and a series of strange, repetitive beeps? While it might sound like your PC is self-destructing, don't panic. This is actually your computer's way of trying to help you.
When you turn on a computer, it runs a diagnostic check called a POST (Power-On Self-Test) through the BIOS (Basic Input/Output System). If the computer detects a critical hardware failure before it can even turn on the display, it cannot show you an error message. Instead, the motherboard uses a tiny built-in speaker to emit a specific pattern of beeps known as "beep codes" to tell you exactly what component has failed.
Different motherboard manufacturers use different BIOS software, meaning the beep codes vary depending on the brand of your computer. Below is a comprehensive master list of the most common BIOS beep codes and POST error codes to help you diagnose and fix your PC.
1. IBM POST Beep Codes
IBM set the original standard for computer diagnostics. If you are using an older IBM machine or a compatible motherboard, refer to these standard audible codes:
| Beep Pattern | Error Description |
| 1 Short Beep | System is OK (Normal Boot) |
| 2 Short Beeps | POST Error - Specific error code will show on the screen |
| No Beep | Power supply or system board problem |
| Continuous Beep | Power supply, system board, or keyboard problem |
| Repeating Short Beeps | Power supply or system board problem |
| 1 Long, 1 Short Beep | System board (Motherboard) problem |
| 1 Long, 2 Short Beeps | Display adapter problem (MDA, CGA) |
| 1 Long, 3 Short Beeps | Display adapter problem (EGA) |
| 3 Long Beeps | 3270 keyboard card failure |
IBM POST Diagnostic Code Descriptions
If your IBM system succ
| Number Range | Failing Component |
| 100 - 199 | System Board |
| 200 - 299 | Memory (RAM) |
| 300 - 399 | Keyboard |
| 400 - 599 | Monochrome or Colour/Graphics Display |
| 600 - 699 | Floppy-disk drive and/or Adapter |
| 700 - 799 | Math Coprocessor |
| 900 - 1099 | Parallel Printer Port or Adapter |
| 1100 - 1299 | Asynchronous Communication Device/Port |
| 1300 - 1399 | Game Port |
| 1400 - 1499 | Colour/Graphics Printer |
| 1700 - 1799 | Hard Drive and/or Adapter |
| 3000 - 3199 | LAN Adapter |
| 4800 - 4999 | Internal Modem |
| 7000 - 7099 | Phoenix BIOS Chips |
| 11200 - 11299 | SCSI Adapter |
| 21000 - 21599 | SCSI Fixed Disk, Controller, or CD-ROM System |
AMI BIOS Beep Codes
American Megatrends Inc. (AMI) is one of the most popular BIOS manufacturers in modern PCs. Their codes are usually a series of short, consecutive beeps.
| Beep Pattern | Error Description |
| 1 Short Beep | System OK (Normal Boot) |
| 2 Short Beeps | Parity error in the first 64 KB of memory |
| 3 Short Beeps | Memory failure in the first 64 KB |
| 4 Short Beeps | Memory failure (Operational or Timer 1 on motherboard) |
| 5 Short Beeps | The CPU on the motherboard generated an error |
| 6 Short Beeps | Keyboard controller error (BIOS cannot switch to protected mode) |
| 7 Short Beeps | The CPU generated an exception interrupt |
| 8 Short Beeps | Video adapter missing or its memory is faulty |
| 9 Short Beeps | ROM checksum value does not match the value encoded in BIOS |
| 10 Short Beeps | Shutdown register for CMOS RAM failed |
| 11 Short Beeps | External cache is faulty |
| 1 Long, 3 Short | Memory (RAM) Problems |
| 1 Long, 8 Short | Video Card (GPU) Problems |
3. Phoenix BIOS Beep Codes
Note: Phoenix BIOS is unique. Instead of continuous beeps, it emits three separate sets of beeps separated by a brief pause. For example, "1-1-3" means: One beep, pause, One beep, pause, Three beeps.
| Beep Pattern | Error Description |
| 1-1-3 | CMOS read/write failure |
| 1-1-4 | ROM BIOS checksum error |
| 1-2-1 | Programmable interval timer failure |
| 1-2-2 / 1-2-3 | DMA initialization or page register read/write failure |
| 1-3-1 | RAM refresh verification failure |
| 1-3-3 / 1-3-4 | First 64k RAM chip, data line, or logic failure |
| 1-4-1 / 1-4-2 | Address line or parity failure in first 64k RAM |
| 2-1-1 | Faulty Memory (RAM) |
| 3-1-1 / 4-3-2 | Faulty Motherboard |
| 3-2-4 | Keyboard controller test failure |
| 3-3-4 / 3-4-1 | Screen initialization or retrace test failure |
| 4-2-1 / 4-2-2 | Timer tick interrupt or Shutdown test failure |
| 4-2-3 | Gate A20 failure |
| 4-3-4 | Time of Day clock test failure |
| 4-4-1 / 4-4-2 | Serial or Parallel port test failure |
| Low 1-1-2 | System Board select failure |
| Low 1-1-3 | Extended CMOS RAM failure |
4. Insyde beep codes
| Beep Pattern | Error Description |
| 5 Short, 1 Long | Problem with the DMA page registers. |
| 4 Short, 1 Long, 1 Short | Circuit for refreshing RAM is not working. |
| 4 Short, 2 Short | BIOS ROM checksum failure. |
| 3 Short, 1 Long, 2 Short | CMOS RAM test failure. |
| 3 Short, 1 Long, 1 Short, 1 Long | DMA controller failure. |
| 3 Short, 2 Long, 1 Short | Interrupt controller failure. |
| 3 Short, 3 Long | Keyboard self-test issue. |
| 2 Short, 1 Long, 3 Short | Video card (GPU) not found. |
| 2 Short, 1 Long, 2 Short, 1 Long | No RAM installed or RAM not recognized. |
Conclusion:
What Should You Do Next?
If you identify your beep code and it points to a specific hardware issue, the easiest first step is to re-seat your components. Turn off your PC, unplug it from the wall, open the case, and carefully remove and re-insert your RAM sticks and your Graphics Card. Over time, these components can become slightly loose due to heat expansion or being bumped, which frequently causes RAM and Video Card beep codes. If re-seating them doesn't work, you may need to replace the faulty part identified in the tables above.