HP 32E Battery compartment tabs

[Steve Simpkin]

(06-07-2022 09:12 PM)KD8TZC Wrote:  Thanks BillBee, I think I understand now.

I did try the small screw method since I did have some around. It can now make contact, and when I hook a voltmeter to the two screw posts, I do get current when I plug in the charger. What I don't have though is a good battery pack, so I ordered one. I seem to recall that HP's won't run without a battery, so I'm hoping that is why the LED's don't come on when plugged in and powered on without the battery. I'll find out in a few days.

Yes, unfortunately the HP-2x (aka "Woodstock") and HP-3x (aka "Spice") series of HP LED calculators used the batteries to regulate the voltage from the charger. You should never try to power one of these models from the AC charger without a good working set of batteries installed that also have a good electrical connection between the batteries and the calculator electronics. Doing so may damage the circuitry of the calculator. The HP-3x Spice models seem to be a bit more likely to survive this but it is still very risky.

Here is a link to the English version Owner's Handbook for the HP-33E. See page 76 for information about battery charging.
https://literature.hpcalc.org/community/...hpg-en.pdf