Radio Shack PRO-2020 (20-112 or 200-0112)

[AF7U]

Greetings everyone, I need a schematic for a PRO-2020 20 channel scanner. The unit has problems with the keypad entry. The front end works fine, even without battery the memory has held some frequencies and those work fine, but the buttons are confused, some work, some don't do what they're supposed to, and some don't work at all. I suspect the matrix decoder? Just thinking... I enjoy restoring these oldies, but having a hard time locating a diagram.
Thanks so much in advance~!
~Michael