| Message | Cause (failure) | Solution |
| 1-1-3 1-1-4 1-2-1 1-2-2 1-2-3 |
NVRAM write/read BIOS checksum Programmable interval timer DMA initialization DMA page register read/write |
Perform visual inspection. If problem persists, see "Troubleshooting the System Board" in Chapter 3 of the Service Manual. |
| 1-3-1 1-3-3 1-3-4 1-4-1 1-4-2 2-1-1 to 2-4-4 |
Main memory refresh verification Chip or data line in 1st 64 K of main memory Odd/even logic failure in first 64 K of main memory Address line, 1st 64 K of main memory Parity, 1st 64 K of main memory Bit failure, 1st 64 K of main memory |
Perform visual inspection. If problem persists, see "Troubleshooting Memory" in Chapter 3 of the Service Manual. |
| 3-1-1 3-1-2 3-1-3 3-1-4 |
Slave DMA register Master DMA register Master interrupt mask register Slave interrupt mask register |
Perform visual inspection. If problem persists, see "Troubleshooting the System Board" in Chapter 3 of the Service Manual. |
| 3-2-4 | Keyboard controller test | Check keyboard interface cable and connector. If problem persists, see "Troubleshooting the Keyboard" in Chapter 3 of the Service Manual. |
| 3-3-4 3-4-1 3-4-2 |
Screen initialization Screen retrace test Search for video ROM |
Perform visual inspection. Check monitor cable and connector. If problem persists, see "Troubleshooting the Video Subsystem" in Chapter 3 of the Service Manual. |