How to fix an old HP41cx

[Jose Gonzalez Divasson]

Hi,

The domes for the upper screws are really the weakest part in the calculator - more so than the screw posts. And gluing them, even with solvent glue, is seldom good enough. What we did was to create a piece with a lot of surface but that matched the lower part of the original battery module:

   

The piece has two sides, and here is cut in two since one dome was still fine. To install it you need to grind down the remains of the dome. Then you glue the piece with E6000, and you can lie the original battery module or the 3D one.

Ignacio Sánchez has given me a lot of ideas over time. This time again: he suggested creating a 3D module with much more surface that can play the role of both pieces: the old module and the back repair part. Then you can grind down both domes and paste the battery module in place. In this picture you see the original module, our 3D part to replace the above, and the new part in case both domes are broken:

   

We have tried it in a couple of calculators with success: the piece stays put and it can be pressed hard without fear.