I found a 486 board circa 1991 on ebay that was having keyboard issues so I grabbed it not knowing much more than that, When I received it, it seemed to be in really good condition otherwise. It’s a Biostar MB-1420/25/33PB/PV
This is a no frills 486 board, no cache no nothing., it has a 66MHz clock tho so its got that going for it.
As expected it was the good old leaky NiCAD trick which ate out the two keyboard CLK and DATA traces, (also had a good crack at the “Power Good” signal but it seems to be fine, for now)
Hiding under the keyboard controller is the 7407
This boards chipset doesn’t have port 0x80 support so the standard diag cards didn’t help here
was still getting 8 beeps, turns out the ram was imbalanced,
The one I have is a DX2OPDR66, the 168pin “ODPR” version but this board has a empty 169th pin for the “ODP” version of the upgrade… shrug,,,