Accu Exchange

Preface

The following accu excange procedure is only intended for professionals!
I am not responsible for any damages or injuries!

Parts

If you own an HP calculactor of the HP32C, 34C or similar series, you'll make the experience, that the internal accu cells might become disfunctional and don't store any electricity any more. That's not unusual, since the original accus are 20 and more years old.

But what now? Expensive repair or do-it-yourself? The answer is easy: With material costs of approx. 5 Dollars and only about five minutes of time to invest, you can change the accus yourself - if you have a little experience in excanging old (and leaked) accus.

List of material

2 AA-accus ("Mignon"). It should make no difference, whether you're using NiCd- or NiMH accus and which capacity they have, since according to my knowledge, there's no charging electronics in the calculator.
If you want to play it safe, you can use NiCd accus or a lower capaticy, e.g. 600mAh, since they're most similar to the original ones.
1 retaining clip, which has to be straightened manually (see photo).

Instructions

Everything installed

At first, the battery case cover is opened by pushing it and pulling it upward, and the old accus are remove. According to the degree of pollution (crystalization), use gloves!
If the original accus are build as accu pack with a metal cage, you can remove the old cells and install the new ones instead. In this case, you don't need the retaining clip.
The old accu cells have to be disposed properly, they do not belong into the normal waste.
In the next step, you might have to clean the battery case (be careful and avoid skin contact of the crystalized leakage!) with a tiny rasp or a fiber glass pen.
The accus are now inserted, either one by one or as package. You have to take care of the polarity:

The upper cell has got its minuspole at the left and connects with the upper contact. The plus pole has got no contact yet or connects with the metal case of the accu pack.
The lower cell has got its plus pole to the left and connects with the lower contact. The minus pole has also got no contact yet or connects with the case of the accu pack.

If the accus are inserted one by one (as on the photo) you have to create an electrical connection beween the two right poles of the accus. The easiest way it the staightened retaining clip. Just insert it properly, like you can see on the picure.

Now you can test the calculator. If the accus are full, it should work now. If not, please turn it off immideatly and check the polarity of the accus and the electrical connection of the two right poles of them.

Finished

Just close the battery cover and you've done it.

Disclaimer