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hp34c compatible charger? - Printable Version

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hp34c compatible charger? - marais - 08-01-2004

I recently acquired an HP34C with a US charger. I was hoping the 34C was using the same charger plug as the classic machines, but unfortunately it uses its own plug (I seem to be the only collector surprised of this fact). Being in need of a european charger, my question would be: SInce I've never seen this kind of charger on ebay, which compatible machines do have the same plug layout? Maybe by bidding for another, less demanded machine, I might get my european charger.


Re: hp34c compatible charger? - Emmanuel, France - 08-01-2004

Dear Marais,
There's several adapters/chargers for this use.
Please see below (non exhaustive list :
HP82090B 220V (France, Germany, ...)
HP82087B 90-120V
HP82119B 115 or 230V (France, Germany,... with pin adapter)
There's also the Reserve Power Pack for Series E calculator (HP82103A).
You can use two 1.5V alkaline or two 1.28V rechargeable batteries. R6 or AA size.
For the last ones, a charger with 2 or 4 slots can be bought from your general store.
Please see my selling list for further information.
 There's pictures and details.

Re: hp34c compatible charger? - db (channeling Norm again) - 08-01-2004

The spice series (31e, 32e, 33e/c, 34c, 37e & 38e/c) are the only ones that use that adapter plug and none usually go really cheap. Still you might just want another model now that you have been bit. If you are not going to save programs; you might consider using AA cells that are charged on a seperate charger, or regular (and maybe slightly pre-used) ones. Charging spice batteries in the calculator is theoreticly dangerous because if the battery is not making good contact you can fry the calc.

Now the Norm part: Congratulations on acquiring the best calculator known to man.

Edited: 2 Aug 2004, 12:12 a.m.

Re: hp34c compatible charger? - Tony Duell - 08-02-2004

The internal charger circuitry of the Spice (HP31E, HP32E, HP33C, HP33E, HP34C, HP37E, HP38E, HP38C) and Woodstock (HP21, HP22, HP25, HP25C HP27) is identical (consisting essentially of a diode and an 8.2 Ohm resistor). The external transformers also have much the same characteristics.

You could therefore use the charger from a Woodstock machine if you changed the output connector (e.g. by using the cable/plug from the charger that came with your 34C). There are 2 versions, the -B is supposed to be used with models with continuous memory. It has a couple of zener diodes in inverse series across the output (I think they're about 18V each), to remove voltage spikes that could corrupt the continuous memory.

Please also read the warnings about charging batteries in continuous-memory Woodstock and Spice models. If the battery pack goes open-circuit, the RAM chip (HP custom, almost impossible to find) can be destroyed. The safest way is to use the reserve power pack, but the one for Spice models is particularly hard to find. Alternatively you could use a non-continuous-memory machine -- even a non-working one -- to charge your battery pack.

Re: hp34c compatible charger? - Jean - 08-02-2004

Someone is selling one on ebay at a reasonnable price.

Re: hp34c compatible charger? - marais - 08-02-2004

Thank you for all your suggestions! I decided to get myself a 38C with a 220V charger. I was not aware of the fragility of the 34C; the idea of an external charger sounds indeed appealing. I'll give it some thought.