I would check for alkaline damage. I've seen many with open traces from battery alkaline. Check schematic and verify continuity with a meter.

Thats a good start. Jump in the T2 forum. I believe Victor, aka DumbAss did an entire recap on this issue in that forum about troubleshooting switch rows and columns and what to pay attention to in the switch matrix. He usually chimes in when he has spare time.

Ken

Good troubleshooting here.

Battery acid (alkaline) can be insidious. You can think you've got it cleaned up and fixed, and then years later it can cause problems.

You've got a board problem here.

You can buy a replacement board. I do this frequently when there is dead switches due to battery acid (alkaline) damage, and the damage is severe.

You can also get the board fixed by sending it to someone like Chris Hibler.

You can fix your CPU yourself, and maybe you'll do good enough repair, or maybe the board isn't all that damaged, and your board might work for another twenty years.

It all depends on how much battery acid (alkaline) damage there is what path I choose.

If you could take a good quality picture of the bottom half of your CPU board, that shows from the battery holder down, that would help us advise you what path makes sense.

Thanks!

Please be cautious of buying parts from ebay. I would use a good supply house like Mouser or Tayda or Digikey