Sony Trinitron KV-27TW70 Tuner Repair
 

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

Sony Trinitron KV-27TW70 Tuner Repair
 

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.

So if power to both the tuner and the vertical section is occasionally interrupted ONLY when the set's tuner is being used (as there's never a picture or sound problem when using a vcr tuner that's connected to the set's rear a/v inputs), does selecting VIDEO turn OFF power to the set's tuner, which could have a short or loose connection?

Thanks, Gerry