The Museum of HP Calculators

HP Forum Archive 08

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Problem with HP41CX
Message #1 Posted by Dennis on 25 May 2002, 6:17 a.m.

I have a problem with the USER button on my 41CX. It's very hard to press and only registers probably every two presses. Anything I could spary it with to repair it??

Re: Problem with HP41CX
Message #2 Posted by Vieira, Luiz C. (Brazil) on 25 May 2002, 10:54 a.m.,
in response to message #1 by Dennis


the contacts for each key in the HP41 are built with a metal bubble (flat) carefully positioned over the keyboard's PCB. All the keys are locked with a self-adherent plastic stick.

Right bellow these bubbles there is a small hole that allows access to the "inside" of the key's contact assy. I read many stuff in here about how to clean their inner guts, and people suggested using chemical cleaners that would not dissolve the plastic cover nor the glue, so they would not disturb the contacts.

I got good results by using thin brushes, thin enough to have their coats inside the small holes. Carefully rotating the brush would allow cleaning the contacts.

I know it sounds vague, but try looking in here, maybe May-December 2001.

Good luck and best regards.

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