ALR BIOS Post Codes:

01 CPU register test in progress
02 Real-time clock write/read failure
03 ROM BIOS checksum failure
04 Programmable internal timer failure (or no video card present)
05 DMA initialization failure
06 DMA page register write/read failure
08 RAM-refresh verification failure
09 1st 64KB RAM test in progress
0A 1st 64KB RAM chip or data line multi-bit failure
0B 1st 64KB RAM odd/even logic failure
0C Address line failure 1st 64KB RAM
0D Parity failure 1st 64KB RAM
10-1F bit 0-15 64KB RAM failure
20 Slave DMA-register failure
21 Master DMA-register failure
22 Master-interrupt mask-register failure
23 Slave-interrupt mask-register failure
25 Interrupt vector loading in progress
27 Keyboard-controller test failure
28 RTC power failure and checksum calculation in progress
29 Real-time clock-configuration validation in progress
2B Screen-memory test failure
2C Screen-initialization failure
2D Screen-retrace test failure
2E Search believed operational on screen believed running with video ROM
30 Monochrome display believed operable
32 Color display (40 column) believed operable
33 Color display (80 column) believed operable