Troubleshooting
Digital DECpc LP
44
MCS Logistics Engineering - Nijmegen
Beep Codes
If the POST finds an error and cannot display a message, the computer's speaker emits a series of beeps to
indicate the error and places a value in I/O port 80h.
For example, a failure of bit 3 in the first 64 KB of RAM is indicated by a 2-1-4 beep code (a burst of two
beeps, a single beep, and a burst of four beeps).
The table below lists the beep codes and the values the POST writes to I/O port 80h when it encounters a
fatal error. This table lists fatal errors that lock up the computer. Nonfatal errors that do not lock up the
computer are listed in a separate table.
Beep Codes for Fatal Errors
Beep Code
Error Message
1-1-3
CMOS write/read failure
1-1-4
ROM checksum failure
1-2-1
Interval timer failure
1-2-2
DMA failure
1-2-3
DMA page register write/read failure
1-3-1
RAM refresh failure
1-3-3
1st 64 KB RAM chip or data line failure
1-3-4
1st 64 KB RAM odd/even logic failure
1-4-1
1st 64 KB RAM address line failure
1-4-2
1st 64 KB RAM parity failure
2-1-1
Bit 0 1st 64 KB RAM failure
2-1-2
Bit 1 1st 64 KB RAM failure
2-1-3
Bit 2 1st 64 KB RAM failure
2-1-4
Bit 3 1st 64 KB RAM failure
2-2-1
Bit 4 1st 64 KB RAM failure
2-2-2
Bit 5 1st 64 KB RAM failure
2-2-3
Bit 6 1st 64 KB RAM failure
2-2-4
Bit 7 1st 64 KB RAM failure
2-3-1
Bit 8 1st 64 KB RAM failure
2-3-2
Bit 9 1st 64 KB RAM failure
2-3-3
Bit A 1st 64 KB RAM failure
2-3-4
Bit B 1st 64 KB RAM failure
2-4-1
Bit C 1st 64 KB RAM failure
2-4-2
Bit D 1st 64 KB RAM failure
2-4-3
Bit E 1st 64 KB RAM failure
2-4-4
Bit F 1st 64 KB RAM failure
3-1-1
Slave DMA register failure
3-1-2
Master DMA register failure
3-1-3
Master interrupt mask register failure
3-1-4
Slave interrupt mask register failure
3-2-4
Keyboard/mouse controller failure
4-2-1
Timer tick interrupt failure
4-2-2
Shutdown failure
