TV problem - white lines

Ok ! Post the Model number and what trouble shooting you have done so far.

The faint white lines are mostly caused by a fault in the vertical blanking process. To service this you would have to be able to troubleshoot the set. What you are seeing by your description, are most likely vertical retrace lines.

The classic way to service this, is to get the service manual, and using a scope and DVM, you follow up on the circuits involved for the vertical blanking.

A few common things that can cause this, is if the CRT screen bias voltage is too high, or if the CRT itself has a fault.

Sometimes you can shotgun this type of fault, by using an ESR meter, and testing all the capacitors in the vertical deflection, and blanking areas. You would then change any capacitors that read out of specs. If this does not work, then you will definitely have to methodically troubleshoot the set.

There are dozens of components involved that can cause the vertical blanking to not function properly. Sometimes a problem in the vertical deflection amplifier stage itself can cause retrace lines. This would be because the vertical deflection feedback is slightly out of phase, and thus the blanking is not occurring at the exact timing.

If you are not properly trained, and equipped to do TV servicing, I would suggest you have the set serviced at a service centre where they are familiar with your model of set. These types of faults are usually not the kind of fault that the end user would be able to service himself. Even if you have a degree in electronics, TV troubleshooting and service is very specialized work.

Also, take care that there are very serious safety issues when going in to a TV set, and working on it.

Unless the OP is an avid hobbyist who has a fully equipped electronics workshop the TV set is probably not worth the time and effort of making a full diagnosis and getting parts to repair it.

I was prepared to dump my TV set but gave it a stab anyway on two separate problems over the years. The fix was of course to give the TV set a few good slaps. But I could never reproduce the problem when I opened up the TV to try to find it.

In both cases it was a cold solder joint. SONY it seems is wellknown for solder joint pads lifting after some years to produce intermittent problems that somewhat responds to room temperature changes as in winter when the furnace fires up. I didn't know about that solder problem then of course.

The first time, after many tries, I happened to brush the harness to the CRT gun and it reproduced the problem. I traced the wires back to the connector plug pins and located the cracked solder joint on two pads. A reflow of the solder fixed that problem.

The second time I used a long wooden dowel to jiggle the wiring until it reproduced the problem. It was also a cold solder joint at a cable connector pin. Try this quick and dirty fix.

Thanks for the replies guys.

Pretty much everything you just said made no sense to me at all though.

But I just wanted an idea as my brother, who gave me the TV knows plenty about electronics, so I'll mention what you guys have posted here and see if he can do it.

Thanks!!!

:-)

He gave you the set because *he* doesn't want to "do it." Otherwise, he'd have kept it....

;-)

jak

You're probably spot on there.

Although he was going out to buy a new one, and he does know his way around TV sets so it would have been a lot cheaper to fix it than buy a new one.

Anyway, I've heard him say before that sometimes, problems with Tv's, often arise after they have been moved around. So maybe it was ok until I got it.

:-)

It has capacitors going weak . All you need is a capacitor checker and a way to replace capacitors . No special test equiment is needed .