again about HP41c display features

[aurelio]

Searching for another problem I've found this thread in the ancient "holy" forum and read this:
"I have a number of very early LCD calculators in my collection, some of them of the 'first-batches' yellow LCD type, and not only do they still work fine, but I can't notice any sign of degradation or diminished functionality whatsoever, despite the fact of them being 25+ years old"

Now, my first 41 was a CX halfnut, so that I cant remind it.......the 'first-batches' yellow LCD type, aren't the ones provided with the tall keys?
It means that the "yellowed" look , it's not due to smoke and to the age of the calculator, as I thought an wrote in a previous thread few days ago......
That could be its natural look!

But now I have with me a Tall key very beauty that came affected by the "greeen" desease.

After a cleaning (the block must be completely restored) I tried a test with a spare one but despite the look very nice it does not give signs of life...
I've tried to replace the board: still not working..

Now I've noticed that the display is not the yellow one, it seems a "new batch" one (fullnut of course) but bright like a CV or a CX fullnut one...it seems it has been serviced (display replacement)......the driver mounted on the first C is not the same for the CV-CX boards? That could be the issue?