HP41CX, not working.

[isanchez]

Hi,

I am trying to repair an HP41cx fullnut version.
Looks like new. It has the typical problem in the battery contacts. I have replaced this part with the model mounted by Jose (thecalculatorstore)

The thing is that it only shows the upper third of the display with an identical pattern (please look at the attached photo). No response at all to the keyboard (none of the keys, even the on/off).

I can tell you what it does NOT seem to be the cause:

-I have replaced the board with a 100% working CV.
-I have used all the zebra models exisiting (the golden old type, two parts golden new type, the one provided by thecalculatorstore).
-The display contacts look absolutely clean, well connected).
-No traces of oxid at all. It looks like new.

The only issue I have in mind could be the display driver, could this behaviour be caused by the failure of the display driver?

Thanks and kind regards

Ignacio