Weird problem in HP 20S

[Marcovecchio]

Thanks for the insight, it makes a lot of sense! I did twist the all 6 posts, but the calculator still doesn't work. I think I'll put it aside for now and try the next one (I have a number of Pioneers to restore), but soon I'll be back to this old 20S.

However, I have found an interesting piece of info here:

https://www.hpmuseum.org/cgi-sys/cgiwrap...i?read=451

It says open switches with leakage below 10Mohms may cause processor lock ups, exactly what I seem to be experiencing. I'll keep trying, thank you very much!

Eduardo