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Arthur Jernberg
 
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Default Zenith Color TV Model # SR2568S Purity & Convergence Question

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



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Jerry G.
 
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Default Zenith Color TV Model # SR2568S Purity & Convergence Question

Can your test gen put out a mid grey type of raster for testing? I have
a feeling that the mask in the CRT is defective, or the purity
adjustment is out. If it cannot be adjusted out with the purity setup,
it has to be the tube, from what I have experienced.

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Greetings,

Jerry Greenberg GLG Technologies GLG
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"Arthur Jernberg" wrote in message
...
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




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