HP 41CX Annunciators Become Visible with Long Inputs

[akpoff]

I have an HP41CX whose display causes the annunciators and other elements in the segments to become visible as you type longer inputs.

If I start with FIX 4 and the x-register is 0.000, the display looks just fine. As I begin to type in a longer number, particularly 8s, various annunciators become visible. It also affects the number segment.

You can see in the image below. I typed all 8s. The batteries are good and I did not have ALPHA selected, yet you can see them almost as clearly as the primary segments in numbers. As I type numbers the displayed annunciators change. E.g., if I stop at nine 8s, the PRGM and ALPHA annunciators are both visible, but typing the tenth 8 causes PRGM to disappear. 1s and 7s have very little effect on the display, 8s and 9s the most.

   

The calculator is a halfnut (edit: fullnut, see below) with nuts to hold the board to the zebra connector. I took the calculator apart and cleaned the zebra connector to be sure. The battery compartment is clean, no damage. I removed all modules and reset the memory. No change.

Any idea what's going on with this display?

--Aaron