GerryO wrote:

Hi,

Picture and sound work great on our Sony Trinitron KV-27TW70, as long
as we use a vcr tuner routed through the rear of the set a/v inputs.
On occasion the tuner works properly, and when it doesn't there's
anywhere from a slightly shrunken picture to a white flat line in the
center.

Believe the tuner has been repaired/replaced once, after possible
damage by a power surge.

Any tuner repair suggestions? Re-solder some specific connections?

Thanks, Gerry


Sounds like two totally different problems.
A defective tuner can give you a snowy picture, total snow, or a blank
or blue screen.
A shrunken picture or flat line are caused by a problem with the
vertical deflection circuit.
If both problems seem to come and go at the same time or seem to affect
each other then I would suspect a problem with a voltage that supplies
both the tuner and vertical section, or loose solder joints in the
related circuits.