Posts: 40
Threads: 12
Joined: Feb 2009
Thanks, everyone. I opened the calculator--which was easy, because someone had opened it before. The problem was immediately visible. There are six little metal "ears" that are twisted to hold the processor board in place. This probably also provides pressure on the connector to the keyboard. The ear near the lower left corner (as viewed from the rear) is missing and the board is angled upward slightly. If I hold the board down there, all the problem keys work fine.
I'd rather not remove the board, because if one tab broke, maybe others will, too. Looks like someone already "fixed" it once before, and twisted it enough to fatigue the metal.
I'm going to experiment with taping a penny or a piece of foam in that corner and see if that provides enough tension. If not...?
Edited: 25 July 2012, 1:54 a.m.