Dying HP41 Displays

[Geoff Quickfall]

Many failure points:

The obvious to the less likely:

1 Contact between module/battery block and keyboard.

2 contact between PCA and keyboard.

1 & 2 depend on good screw posts; not cracked or stripped posts.

1 depends on a foam insert on the module/battery not being compressed over time. Similar to the foam inserts on the pioneers.

2 depends on a) zebra strip contact or b) wire wrap with foam insert which can also fail due to age.

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3 cold solder joints on the LCD strip.

4 zebra strips built into the LCD panel assembly.

5 LCD drivers.

I have seen 1 through 5 cause display problems. 1 through four are repairable, 5 needs a donor panel.

Cheers, Geoff