Arfa Daily wrote:
I can't for the life of me think what that problem could
be, to cause that symptom. And not any kind of sync issue that I can think
of either. The picture was perfectly stable in both the H and V directions.
Very odd ...

Perhaps it's a "flywheel" PLL sync issue around the part of the circuit
that de-interlaces and reads lines of video into the digital frame buffer.

However it has got problems with recognising the pixel timing of new
lines in the first field, comes in sync after a few lines, successfully
uses the now found timing to digitise the secong field, then, er, forgets?

--
Adrian C