Hey everybody,

got back in the hobby again and decided to revisit an old project of mine. I’ve got this UM8810PAIO rev 2.1 board I got ages ago as my first ever retro pc purchase. I remember doing some testing with a torn apart keyboard and something went wrong, the board made a lot of unhappy beeps and after turning it off and on again it didn’t recognizance any keyboard anymore.

I now would like to figure out whats broken, I like the board and the rest seems all fine. I swapped the BIOS, BIOS chip and the keyboard controller, didn’t do anything. I tried another keyboard and instead of just nothing on the keyboard the LEDs a flickering faded all in sync and more unhappy beeping. I stopped testing with that keyboard since it wasn’t working anyway and the beeping gave me bad flashbacks..

Cutting to the chase, I checked voltages on the backside of the board, and I’ve got a 4,7V reading on the middle pin and on both most outer pins. Looking at the pinout and comparing with another board this isn’t right, right?

So anybody with the board who could take a look on which part I now should test/swap/etc?
There is also a bridge between one of the pins and a pin of one of the ps2 port solder pads, I assume this is all correct and factory like that?

Anyway, thanks for taking the time and best regards,
Eleanor1967