Recovering non-responsive buttons on 42S

[mats]

Thanks very much to GrayUser and BillBee for the ideas. I searched the forum for "42s repair" and got lots of results (I had previously tried searching for "repair 42s" and found nothing which is when I posted my own question - I should have known better .

Like most of you I have had many HP calculators over the years. I had a 15C (made in the US) for 25 years before I lost it - it never had a problem and it was used a lot and I loved it. I think I paid about $100 for it in 1984 which was a lot for a graduate student. I recently found an almost identical 15C (1988) on eBay for $200 and bought it, and it made me so happy that I decided to try to revive my old 42s (1987) and 48G (1993), both made in Singapore, that died many years ago. Hence the question I posted.

Just to add some data-points to the posts I have read about the longevity of other models, I have three 35s calculators and I love them (in principle) but in practice all but one developed keyboard problems after about a year of light use. The one that survives was made in the Philippines, and the two crippled ones were made in China. I also bought a 49G some years ago, perhaps out of fondness for my old 48G. As far as I know it still works fine but just don't like using it so its basically brand new.