HP 41CV intermitent fault

[Nigel Bamber]

I have been given a 41CV which requires me to keep squeezing the front/back together at the bottom of the calculator in order to keep it working. Otherwise the display goes blank and I need to squeeze it again and then press the ON key in order to get it working again.

I suspect the calculator hasn't been used for sometime.

What is likely to be the cause ? Should I take it apart and try and find the lose connection if that is what it is ? Or should I not take it apart and try to fix it with some tape ?

All help appreciated ?

Nigel

[PeterP]

This is one of the most common ailments of the 41 series (next to corrosion). Most likely a broken post or two. If you carefully shake the calc I would not be surprised if you her some rattling. And/or you can probably see/feel that the top and bottom halve are not fitting together strongly. There are a few threads you can find here on this ailment (search for things like 'broken post', 'funny display', 'display @', etc). it can be repaired, but can be finicky.

Also check out this articleRepairing an 41CX

Hope that helps.

Cheers

Peter

[Nigel Bamber]

Thanks for the advice Peter. I opened her up and discovered the expected cracked posts. I took fright at their repair and decided on a different tack.

The screws in fact hold themselves quite well but not just not well enough. Also squeezing the bottom right hand side resolved the lost contacts issue. Therefore I decided to attach a little plastic washer inside the back of the case to increase the pressure on the flexible PCB and it worked !

The calculator now turns on and off normally without those funny characters in the display.

Cheers

Nigel

[Geoff Quickfall]

Yes the posting about new wires and etc are daunting.

I just repaired a 41CV with two cracked posts and the same contact problem.

Unfortunately the fix you have done is temporary as the cracks wil propogate, especially now since the compression is putting more stress on the the posts and cracks.

I am posting the repair as a new topic as this is falling by the wayside.

Cheers, Geoff