[Coco] CoCo 64K (26-3126) Keyboard Issues Follow-up

[Christopher]

Folks,

Thanks for the replies.

A quick follow-up:

1) No joysticks are plugged in.
2) I disconnected the keyboard ribbon cable, checked continuity across each
conductor, seems fine. Unplugged and replugged in the keyboard several
times in case there's oxidation. No effect.
3) It doesn't look like the keyboard's ever seen a spill. It's immaculate.
Admittedly, I haven't taken it apart. I'd consider doing that if I had some
instructions.
4) The PIA in this unit is a 6822. I had a spare 6821 and swapped it in.
Saw a similar issue. (I've read the 6821 isn't necessarily a direct swap
for the 6822?)
5) For the most part, the issues seem to occur across keys mapped to pins
9, 10 and 11 on the matrix, e.g. pressing 1 or 2 gives "12" on screen,
pressing Break clears the screen and inserts a line feed, etc. I'd say the
issues definitely seem localized to keys mapped across pins 6 through 11.

I don't have another PIA to test with, so it looks like I may be out of
luck on this unit. If it turns out this is not a quick fix or is otherwise
out of my skillset or available parts, I'd be willing to part with it for
the cost of shipping if anyone is interested.

Thanks,

Christopher