Yeah, I've flipped it a bunch and cleaned it with CRC QD Electronic Cleaner. It's much better than it was. Probably just needs some more "back and forth".
I think it is that keyboard connector. I just took a few minutes and removed the 4 screws that hold the case together and lifted the top. I jiggled the ribbon cable around in the slot and it started working again.
While typing, it would drop out, wiggled it some more and it started working again.
I noticed that the way it wraps around it sort of makes this type of connection in the slot |/| (where | is the slot sides and / is the pin). I pushed the ribbon so it made more of a straight ||| connection and so far seems good.
Pulling the SIO cable out of the port must have been enough to make the connection flake out again. I think the port might just be a standard pin connector. I might even have some floating around somewhere. Other thought I had is that I could tin the tips of the keyboard pins with some solder and see if that makes a better connection before trying to replace the main board connector.
side above the jumper resistor? A trick with dirty switches is to move them back and forth a bunch of times, like 100 or more, until the contacts clean themselves off. If it's one of the more open types, you may be able to squirt some CRC 2-26 (from Home Depot) in there to help clean the contacts.... more
I think it might be a piece of paper towel- Erik_,Tue Sep 13 2022 1:53pm
I never got the tools to properly work with one, but they're pretty straight forward. You can probably put a new end on by smashing it into a new connector, but who knows how good of termination you'd get. If it's like an IDE cable, it's just headers and sockets.
Here's a pic I found online It's more like through hole IC pins on a "ribbon" like cable. I could solder another connector that plugs into the board onto these pins but might be easier to replace the socket on the board first.
Hopefully that's where the problem is. I think I saw something like that on a "make it a 286" chip upgrade. You pulled the 8088 out of the motherboard and plugged it into the board. You could then switch via a toggle switch between your 8088 and 80286. Of course the cable is missing on mine!