TV with sound but no display

[AMalonzo]

Hi there everybody,

Pls help me with my SOny KV20M10C. It only has sound, but no picture(blank screen) what i can see is only trace lines(RGB). Previously the problem is a vertical fold over image at the top, when it is turned-ON you can see only the trace lines and it took so long for the image to appear clearly. had encountered this before but without the trace lines only blank screen. The unit turned OK after the screen voltage was adjusted.As of now, still done nothing at all. Is there any posible fault that causes this problem. Hope for any response. :roll:

Thanks in advance. :lol:

Regards,

Alvin

 

[TheOne]

The IC used for the vertical output is most probly faulty or have some dry joints. The line stage is working since you can see fly-back lines and have sound. If you have a scope and a diagram it should be quite easy to locate the problem. There are often some electrolytics around this IC than can short or dry up and go low in value.

 

[Nigel Goodwin]

As TheOne suggested it could well be dry joints on the frame output chip, it's a common problem on Sony TV's. However, it's also quite possible it's killed the chip, so that could need replacing as well.

 

[FRIED]

Typical vert o/p. Your pin numbers may be different. On p8, the "situp" or
"pumpup" cap between pins 4 and 9 is a cause of foldover.
https://www.fairchildsemi.com/ds/KA/KA2142.pdf