| Beep Codes | Error | Probable Causes |
| 1 | Memory refresh failure. | Defective system board. |
| 2 | Error occurred in first 64 KB of main memory. | Faulty DIMM or defective system board. |
| 3 | Read or write error occurred in first 64 KB of main memory. | Faulty DIMM. |
| 4 | Timer on system board malfunctioned. | Defective system board. |
| 5 | Microprocessor error. | Defective microprocessor. |
| 6 | Gate A20 failure. | Defective system board. |
| 7 | Microprocessor-exception interrupt error. | Defective microprocessor. |
| 8 | Video memory read/write error. | Missing or faulty video adapter. |
| 9 | ROM checksum value does not match value encoded in system BIOS. | Corrupted system BIOS program or defective system BIOS chip. |
| 10 | CMOS shutdown register read/write error. | Defective system board. |
| 11 | Cache memory error. | Defective microprocessor or cache card. |