Re: hp50 = second harmonic of hp25

On Tue, 25 Jul 2006 12:40:56 -0500:

need to get some replacment nicad batteries for them.

For HP25 (and all "Woodstock" series),
any NiMH "AA" cells should be fine
(the pack is so roomy that common "button" cells
still fit, with much room to spare).

If the battery pack still has the original
plastic strip which prevents battery removal,
that strip can be cut away without concern,
to enable easy battery replacement at any time
(just make sure to mark and observe
correct original cell polarity and direction).

VERY IMPORTANT:

NEVER plug in AC power/charger if battery pack
is dead (or batteries or pack not inserted),
because the power supply is UNFILTERED,
except by the batteries themselves[!],
and may well "fry" the calculator in that case.

The same applies to the "Spice" series (HP3xE/C).

Thus, even these "grand old" HP calculators
left some aspect of their otherwise brilliant engineering
a disaster waiting to strike -- why?

[r->] [OFF]
.

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