Hi, these sites have POST codes:
http://mrbios.com/techsupport/award/postcodes.htm
https://blog.theretroweb.com/2024/01/20/amibi … ost-codes-list/

The 0102/0201 codes are missing, though.
Could it be that they're are repeated 01-02, 02-01 code pattern?

If so, then it means the first two stages of CPU test (01: NMI, 02: CPU registers) would have passed.
The 03 would have been BIOS checksum..

It's just a thought, I don’t know how this AMI BIOS works..

Good luck! 🙂🤞

Just on a very off chance - did you hook up a reset button and try resetting it?

I did run across a board once that basically relied on the IDE hard drive being present to reset.
Otherwise you had to manually reset it (via a in on the front panel header)

If the BIOS checksum is not completing, try reseating the BIOS (and other removable ICs) and/or cleaning legs with isopropyl alcohol & a toothbrush. They build up oxidisation and don't contact well over time.

Thanks for your input! There is some progress. I cleaned the legs of the BIOS chips with alcohol, and after I put them back in, the system POSTed but got stuck on an '8042 A20 gate error'. I then powered the machine off to look up what this means, but when I turned it on again the original problem re-appeared.

Intel 8042 is the type of microcontroller used for AT keyboard controller.
It controls the A20 Gate, it does connect/disconnect the higher address lines of the processor to the bus/to the extended memory.

Isn't that 8042 usually close to the nicd battery? OP does not mention any corrosion, but there can be something minor.

Removed the keyboard controller, cleaned it, and now the system does 1 long beep and 3 short beeps, which indicate a memory issue, and displays post code 30, which also indicates a memory issue.

I suspect that pretty much all socket IC's on this board don't make good contact anymore and the motherboard is edging me on to clean every one of them 😀