HP33 Display, contact corosion?

[teenix]

The connections look pretty good, so maybe it is just poor connections between the display pins and the flexible circuit board. There is a spongy film that is partly there to support the display pins and hold them against the printed circuit contacts when everything is assembled. Maybe this has degraded a bit over time and has flattened out.

I guess you would need something thin inserted against the original padding to increase the pressure on the connections.

cheers

Tony