Classic Battery spring replacment

[HP-Collection]

Hi

Got a nice HP35 today, but one of the battery springs is corroded.
Did someone ever change the battery springs of a classic calculator? How can the black plastic be removed so that the spring can be desoldered?
Matthias

[grsbanks]

You'll have to remove the back cover for that, I think.

That, in turn, entails removing the screws that are hidden behind the label, the removal of which can be destructive if you're not careful.

If you heat the back label with a hairdryer or similar, you should be able to peel it off without damaging it.

[HP-Collection]

Missunderstanding: I removed the back shell of the calculator, but the the solder point off the battery contacts is covered by a black plastic I can not remove.

[Harald]

(11-19-2019 06:49 PM)HP-Collection Wrote:  Missunderstanding: I removed the back shell of the calculator, but the the solder point off the battery contacts is covered by a black plastic I can not remove.

If you have already taken the back off, you will see a couple of screws around the outside of the plastic part you are taking about. These fix it to the calculator front. Just undo those and you can take everything appart.

Cheers,
Harald