Highly suspect actually is the crt.
"Randy J. Evans" wrote in message
om...
Zenith Color TV
R-Line
Model # SR2568S
Chassis # C10

The Purity is excellent, the Convergence is off only slightly, and
shouldn't
be noticeable to an untrained eye. The problem is the lower half of the
picture has a green cast to it at times, especially when the camera goes
from a fairly close up shot, to a camera shot that is pulled back, for a
panoramic type view. If a camera shot has someone centered on the screen,
from their neck down it has a green cast, the fleshtones from their neck
up
are not too bad, and near the top of the screen it will also take on a
greenish cast.
This set uses an LA7672 Jungle IC, and the Picture Tube is # A63AGD01X
At times the picture looks perfect, although every few seconds, you can
actually see the Tint change, like some type of Correction Circuit kicking
in. I've seen this on a few other Zeniths, and it's a very annoying
phenomena.
So, using an NTSC Pattern Generator, Purity, and Convergence looks A-OK,
but
when actually receiving a broadcast signal, the problems present
themselves.
The B&W Tracking is good, as is Vertical Size, and Horizontal Width.
I know my that my explanation of the problem is sketchy at best.

Any Ideas appreciated ??

Thanks,
Randy J. Evans