HP 25 and HP55

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Oct 21 18:43:29 2004

> I just got some HP calculators!


> Now I have some questions :^)
> --Anyone have a spare manual for either?

You should by the CD-ROMs from the Museum of HP Calculators
(http://www,hpmuseum.org/). You should find scanned user manuals (and
maybe program libraries, etc) for both machines there. If you want
schematics, then I think HPCC can help out...

> --Have pointers on replacing the battery pack on the 55?
> (it seems to be 3 AAA nicads)

It's 3 AA NiCds in series. Nothing more.

> --Anyone have any pointers on cleaning up leaked nicad crystals?
> what is that stuff anyway?

It's some alkaline compound, you need a (chemically) weak acid to clean
it up. I use a dilute solution of citric acid (this stuff is somewhat
hard to get in the UK, althought it's pretty harmless. I am told that
drug pushers (the illegal kind) use it to 'cut' their wares, hence the
fact that anyone buying it is viewed with suspicion :-().

> I do have cases and power suplies.
> -- I took apart the 25's battery pack and replaced the nicads with
> nickel metal hydride cells (the same ones I use in my camera)

Should be OK.

> -- Is is ok to run the 55 on wall power supply without a battery
> pack installed?

Yes. It is safe to run the 35, 45, 55, 70, and 80 (but _not_ the 65 or
67) on that PSU without a battery pack. Don't run _any_ 2xC or 3xC (25C,
29C, 33C, 34C, 38C) or 95C on the adapter without a good battery pack
installed, you are very likely to damage ICs).

Received on Thu Oct 21 2004 - 18:43:29 BST

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