The Museum of HP Calculators

HP Forum Archive 16

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Charger for Classic
Message #1 Posted by Giancarlo (Italy) on 3 July 2006, 2:24 a.m.

Hi everybody on the Forum.
Is there the possibility to build a charger for a Classic from scratch?
Would it be possible to use one of the many chargers around for other devices?
And waht about the connector to the calc?
I couldn't find a lot on this matter over the Museum (OK, batteries are well covered)
so any suggestion would be very welcome.
Thank you all.
Ciao.
Giancarlo

      
Re: Charger for Classic
Message #2 Posted by Walter B on 3 July 2006, 2:39 a.m.,
in response to message #1 by Giancarlo (Italy)

Why? There are plenty of them on the market. If you send me an e-mail I can offer you one with European plug and voltage, working for sure.

Regards, Walter

      
Re: Charger for Classic
Message #3 Posted by Hal on 3 July 2006, 6:34 a.m.,
in response to message #1 by Giancarlo (Italy)

Hello Giancarlo,
The charger for a classic is actually two power sources in one...
A constant voltage source of about 5VDC to run the calculator,
and a constant DC current source to charge the batteries (which measures about 12VDC unloaded as I recall).
Building one, while not impossible, would certainly be a home science project.
I would tend to agree with the previous responder...these charger are widly available on E-bay for a reasonable cost.
Best regards, Hal

            
Re: Charger for Classic
Message #4 Posted by Gene Wright on 3 July 2006, 8:50 a.m.,
in response to message #3 by Hal

Widely available on Ebay? Not that I've seen.

I'm searching for a couple of these myself and haven't seen one offered alone in a week and a half.

They are offered with a classic HP, but I haven't found them solo.

?

Gene

      
Re: Charger for Classic
Message #5 Posted by Klaus on 3 July 2006, 6:51 a.m.,
in response to message #1 by Giancarlo (Italy)

The article forum contains the schematics for the charger:

Tony D.'s article

      
Re: Charger for Classic
Message #6 Posted by David Smith on 4 July 2006, 6:44 p.m.,
in response to message #1 by Giancarlo (Italy)

Building the electronics is fairly trivial... building the connector is not. Bite the bullet and either buy one on Ebay (hint, it is often more cost effective to buy a classic with charger than a bare charger. Warning: a LOT of chargers have damaged connections in the molded rubber plug) or else charge the batteries external to the calculator.


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