HP 41CX Annunciators Become Visible with Long Inputs

[akpoff]

(01-22-2023 02:41 AM)aurelio Wrote:  Hi Aaron, I've not yet idea of what is going on with your calculator, still thinking about it..
anyway the calculator seems to be a fullnut and not "halfnut"as you wrote
regards

Hi Aurelio,
You're right. I misspoke, as it were. It's a fullnut. Thanks! Here's a photo if that helps.

   

Further update for anyone else following along:

I took the board off and cleaned under the zebra connector. I also tested continuity from the soldered connections on the display to the board. I tested both where they connect near the display at top of the board, as well as tracing the connections as far as down they go and tested. Continuity is good AFAICT.

I exchanged battery packs with another calculator to exclude power issues. Both calculators worked as before with the swapped battery packs.

The problem persists no matter what I do.

I have a 41C with a fullnut board in it. I could try swapping them to see whether the issue is unique to the board or the display. Does anyone know whether swapping between models will work?

Cheers,

--Aaron