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On more question about 82120A HP41C battery pack repair. - Printable Version

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On more question about 82120A HP41C battery pack repair. - Frédéric ALBERT (from France) - 09-12-2002


Today is a great day for me because I decided to try to repair an 82120A battery pack for my 22 years old HP41C. Alas, at the moment of the breakdown due to a leakage of the cells many years ago, I dismantled the pack in a rude way. Today my problem is that I have gathered the different parts, I mean:

·The case in two parts that I think I will be able to glue back together,

· The connector or plug: it is a three contacts plug with the middle contact for a switch (I don’t know if this switch is useful and/or used)

· Two small hooked leaves: I think that they are useful for the contact with the calculator

· And the internal board with no external connection (alas I have cut all the wires !!!!!!)

The problem is I have absolutely no idea about the connection between the plug and the board (where to connect the two AC entries from the charger block on the board. And if the switch is used and so connected but where????) ……. And where and how to connect the battery cells.

I do not have anymore the old cells. I do not know which size of cell to use (½ N or 1/3AAA). I do not know which type of cell to use (does this “old” board support NiCad or NiMh or another.).

I suppose (but it is a supposition) that the cells have a voltage around 1.5 volts so I suppose that they are chained…. But are the intermediate points connected to the board, or is the board only connected at the two ends of the chain of cells????

Does anyone have an electrical schema of this board and of the whole battery pack?

I can send by mail images of the two face of the board, if someone can help me.

Many question for an operation I would like to be a success, because I wouldn’t like my loved old HP 41C purchased in April 1980 to die …… sniff.

I have read plenty of threads and articles on this forum, but I haven’t seen any schema of the 82120A battery pack.

Any help, any advise, any link on forum’s thread or other site, will be really greatly appreciated. On this forum or directly by email.... especially if explanations could be given in French (you may have noticed that it is my mother’s language and the reason of my poor practice of English [I do not tell you how many time and translator accesses I have had to do to write this message]).



PS: my next step, after the success I hope, will be two repair my old card reader (to be used with my new battery pack!!!!). By the way does anybody know what is the translation of O-ring en French???

On more question about 82120A HP41C battery pack repair. - Hugo (Belgium) - 09-12-2002

i can only help you with the translation: an o-ring in french should be "joint torique":

salutations, Hugo