IBM Model F 122 xwhatsit troubles

[themavery]

Hello Geekhack community,

This is my first post here, but I've gotten lots of good information already about the xwhatsit keyboard controller from here. I soldered up my own controller. I'm not totally sure what's going on here, but I've tested several things and haven't found any faults yet. The trouble is that the controller thinks that every single key is pressed down on the keyboard at the same time. It seemed indicative of a ground fault, but further testing showed that ground was connected it was supposed to be. Where I'm at now is that possibly one of the ICs (or maybe a capacitor) is dead. Any help would be appreciated.

Picture of my board:



Screenshot showing software thinking all keys are simultaneously pushed down:


Thanks in advance!


(P.S. I'm typing this on a Unicomp 122 key keyboard)

[120sabot]

Hero themavery

What happens if I change the current threshold value of the second image to 140?

In my Model F AT and 3178C4, 135 to 140 are sweet spots.



I apologize in advance, but I'm Japanese, so I'll leave the English translation to Google translation.