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HP41 Display Problem - Printable Version

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HP41 Display Problem - Fouad M. Kaadou - 06-23-2012


The screen on my HP41CX does not display all the segments. It only faintly display the top right segments.
This just happened. What should I do?

Thanks in advance,

Re: HP41 Display Problem - Frido Bohn - 06-25-2012

Hi Fouad,

I just browsed around in the HP Museum's website to look for references around the keywords "broken posts" - by the way, would be a good title for a movie where the HP41 plays a substantial role :-)

I was surprised to find a thread as of 25th Sep 2011 which was started by you and dealt with this problem.

I believe that the problem with the unreliable display has its roots in a flawed connection between the board and battery compartment.

If you apply a firm grip between the upper rubber feet (on the opposite of the display) and the contralateral part on the keyboard side, would you notice any changes in the display?

If so, then it appears to be a classical "posts problem". Either it is broken, its screw thread doesn't grab anymore (over-tightened screws?) or the back-front connection isn't tight enough.

In any case there are tons of materials in this site to aid the diagnosis and resolution of this problem.

My personal favorite is this although I never applied it. But the solution with brass posts appears to be the more stable and definite.

Re: HP41 Display Problem - Randy - 06-25-2012

Absolutely nothing to do with "broken posts". Three possible problems:

1) Defective display driver

2) Defective LCD

3) Bad interconnects between #1 and #2

Re: HP41 Display Problem - Fouad M. Kaadou - 06-29-2012

Hello Randy,
How do you suggest I test for your proposed possible issues?