Andrew said:
I repaired some old HP calculators once. It wasn't too difficult as it
was mostly made up of transistors, caps, transformers, buttons, hex
tubes etc. It is worth your while to learn basic repair on such old
beasty's.
Andrew
I don't think they are really that old.
Obviously, "old calculators" could mean many things, including
mechanical. But the "digital diaries and databanks" suggest
things far more recently.
I bought an HP-55 at a garage sale a few months ago, and if there
are any transistors in there, they are of a limited nature.
Worn out rechargeable batteries are likely a problem. Missing
chargers another. Leaked batteries that have caused outright
damage to the circuitry. Keypads that have gotten dirty.
Of course, the original poster didn't give an indication of whether
these things are outright dead, of merely partially operating. Dead
may mean a relatively simple thing like a bad battery or on-off switch,
but partially operating give clues while may be more troublesome
to fix.
Obviously one should do websearches when they bring such things home.
Because it can be surprising how often one can find a manual online,
be it from the manufacturer or some third party. If the item has some
"collector value", chances are even better of finding information, since
people aren't going to bother fixing that $3.99 LCD calculator, but
might find some value in keeping that 1975 calculator going, or that
1976 LED watch.
Michael
