Posts: 252
Threads: 14
Joined: Jan 1970
Tom,
The battery pack WAS common to other calculators... some 25 years ago. Unfortunately, these battery packs cannot be found in stores.
It is, however, possible to rebuild an old battery pack using modest skills, a few tools, and NiCd battery cells that can be obtained, for instance, at Radio Shack. You haven't thrown out your old battery pack, have you?
Viktor
Posts: 1,162
Threads: 26
Joined: Aug 2005
The battery pack for the HP80 is the same as the one for the HP35, 45, 55, 65, 70, 67, and 75. As far as I know it was specially made by
HP for these calculators, and no other standard battery will drop in.
If you still have the old battery pack, it's possible to cut the plastic apart, remove the old cells and replace them
with new ones, using the original plastic housing and contacts. It's just 3 AA size NiCd cells in series.
If you don't have the original pack, then you might be able to find some way to connect 3 AA NiCd cells in series to the contacts in the calculator -- the contact nearest the front of the machine
is +ve. Also, with the 'classic' machines without card readers (35, 45, 55, 70, 80), it is perfectly safe to run them from a charger without
a battery pack installed. When the charger is connected, the battery pack is disconnected from the calculator. The charger unit is electrically in 2 sections, one is connected to the battery and charges it, the other
is connected to the calculator electronics. The second part is not affected if there's no battery connected. This DOES NOT apply to
those models with card readers (65 and 67) -- on those, plugging in the charger without a good battery pack installed risks damaging the card reader chip.
