Testing a Woodstock Power Supply

[Mike T.]

I've been luck enough to acquire a Woodstock power supply 82010A which looks like it should be suitable for my HP25 - Thanks Klaus.

This raises to two questions

How do I test it without connecting it to the calculator?

Assuming that it does work is it safe to rebuild the HP25 power pack with NiMH batteries or should I did out a couple of an older NiCad batteries if I intend to use this power pack to charge them?

I note the warnings about charging batteries in the calculator but it does not look like it will be possible to get them in/out of the battery pack without them working loose in operation.

Unfortunately I've only got an old fashioned moving coil multimeter, nothing as fancy as an oscilloscope!

Mike T.

[Dia C. Tran]

A lot of people who frequent this forum would probably know more than I do about this subject. The power supply for the Woodstock series is just a step down transformer. I believe the output is about 8VAC. You should be able to use NiMH in the 25 battery pack and charge it with the charger without any problem. Charging time is much longer but the battery also lasts much longer too.

[Bram]

Quote:

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I believe the output is about 8VAC.

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On my charger itself 10VAC is specified. I think it´s converted to a constant 50 mA current to charge a NiCds of that time. Hence it took 14 hours or so for a full load of power.

I do not know the charging specs for NiMH, but they very well may "digest" the 50mA=.

Anyway, you can easily check the voltage of the charger.

[Mike T.]

Thank you. I'l clean it up and see how it goes

Mike T.