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HP28S battery stuck! - Printable Version

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HP28S battery stuck! - Tom (UK) - 02-13-2002


I recently got hold of a HP28S in good working condition for 6 pounds (about $9) but the 'inner' battery is stuck in the machine.

The single battery comes out easily, the first of the double batteries only comes out if I slap the calculator into my hand a few times, the last battery will not budge!

I can see a rubber strip that seems to be stopping the battery coming out because it is twisted. Can I cut this to try and remove the last battery? Does this rubber strip simply stop the batteries rattling?

The other thing I think might work is if I make a small tool by bending over a stiff wire, sliding it down the side of the battery and pulling - but I think the wire will bend.

A destructive method might be to drill a small hole in the hinge side of the calculator and push the battery out - but I don't want to do this.

Has anybody seen this problem on a clamshell HP, and if so how did they solve it?


Re: HP28S battery stuck! - Vassilis Prevelakis - 02-13-2002

How about adding a drop of glue (e.g. epoxy) to small rod and attaching it to the visible part of the battery.

Leave it overnight for the glue to harden and then pull on the rod.

If this fails, try a very long-thin screw.

You may also want to add a bit of electrical contact lubricant to make the battery slide out more easily, but only after you try the other two methods, because once the lubricant is in there, nothing will ever stick on that battery.