HP41 rechargeable pack repair


I got a NiCd pack, almost surely dead. I would like to repair it, but I can't find a safe way to open it without breaking the plastic enclosing.

The same apply to doubling a X-Memory module, should I break the enclosing for sure (like Cristoph says in his book) using a knife, or a lower impact approach exists?

I have another repair to try, a card reader that works well, but one spring on the lock mechanism is not working.
Is it worth to try to repair or better to leave as is?

Giuseppe Marullo


I have repaired several HP-41 battery packs. I have tried using an exacto knife and an exacto saw. In my opinion, the saw works much better and gives you a nicer looking finished product. I have refit the batteries with 1/3 AAA NiMH (nickel metal hydride)soldered in series. Glue the finished pack together with airplane glue. Paul.


thank you for your answer. Do you have any photo about the hack? I would like to see an example on how to cut it neatly, this things are not easy to find.

The same apply to the X-Memory modules? Do I need to cut the envelope, no other way?


Pictures shown the opening up of a memory module may be found at ji's web site:


I'd also use an exacto knife to create the line where
the two parts will separate (i.e. don't try to cut through,
just create a single continuous scar along the joint, the plactic will open up like a broken zipper once you apply pressure with the blade as shown in the pictures).



thank you about the link, I will try it. Thanks to Paul, I find the courage to open the battery pack, I will post photos this evening.
I am buying the 1/3 AAA 120mA/h batteries, since the 220mA/h I got are too big for the rechargeable pack, given I will keep original electronic and connector.


I slice around the joint between the two case halves with a single edge razor blade. This can be rather difficult and time consuming (and a bit dangerous). A saw is easier but can remove too much plastic.

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