Right sitrep! The speaker?!

The 'audio' is generated from the chipset, then buffered through a f244 ic and then into a 33ohm resistor then the speaker. It modulates the ground and +5v is supplied to the other side of the speaker through the positive bus.

I pulled the 244 and tested it, it was fine... Traced some wiring, had a look at the traces, reflowed one side of the chipset IC and... It works!!

But here's the best part: it might always have worked, 'cause turns out the MR BIOS doesn't generate a post beep at all, and I took this to be a sign the speaker circuit was broken! 🤣

A few beep and play statements in qBasic made for a better test and all seems well.

Well, anyways, I also finished off recapping the board and I'm glad I did: a few of the tantalums just sort of fell apart on removal!

Oh no! My AT keyboard is getting flaky.

Designed a wee PCB that should convert most AT style motherboards to a PS/2 option:

https://github.com/ChrisWIP/PS2AT