Following on from my slightly OT post of a few weeks ago regarding the
'impossible' H linearity error that I saw on the Delta in-flight LCD screen,
tonight, I saw another. This time it was on an LCD screen at my local bingo
hall. I would guess that it's about a 22", standard 4:3 aspect ratio. Used
to display numbers when they are playing tabletop cash bingo, and winning
cards during normally called bingo. There are many screens around this large
hall, all being fed from the same primary video source, so I think that
incoming signal can be eliminated.

This one had a 'foldover' of about 1.5" at the top left corner. It
progressed across the screen getting less and less, until at the right hand
side, the top of the picture was absolutely normal. The 'foldover' was
extremely non linear. It looked to be very stretched, to the point where you
could see what you would describe as individual scanning or field flyback
lines - if it were a CRT display ...

I thought I was reasonably au fait with the way an LCD screen was driven
from its frame buffer, but I'll be buggered if I can see a way that data
could be read out erroneously, in such a way as to produce a badly stretched
tapering wedge of foldover, across the top of the screen. Anyone seen
anything like *this* one, or have any suggestions how it could occur ... ??

Arfa