Repair Shop didnt fix it!

[Gronkus]

the picture on my 27" Sony Trinitron still bows inward on each side. It gets worse if the colors on the screen are brighter like blue and white. I dont know what to do with this it is driving me nuts, it only seems to be happening on the video inputs, normal RF appeared fine at the tv shop when they turned it on.

[wkand]

I don't know what model of Sony you have, nor am I familiar with the circuits on Sony sets, but your set sounds like it has a pincushion correction problem. In solid state sets this is usually a function of one of the combo IC's, related to deflection-generation, or video. I wouold go looking for the problem there, particularly a problem with electrolytic capacitors. It probably is not any of the IC's that are bad. Beware if you suspect an expensive part! Also, are there any menu driven adjustments possible. At the extreme end, this may be a deflection yoke problem.

[radiotvnut]

I second that it sounds like a pincushion problem. Unfortunately, there are many things that can cause such problems. Defective caps would be the prime suspect followed by defective transistors in the pincushion correction circuit. May I as what the TV shop did to supposedly fix it?

[wkand]

Wooops! Didn't see the part in your post about the bowing problem only occurring on external video input, so forget the video driver circuit and deflection yoke causes, but I'll stand by my earlier analysis that there might be a video problem, but only in the video input circuit.

[Duane]

You posted this topic on another thread.Did you read the pdf file that findem-keepem attached to his post?Why couldn't the repair shop fix it?

Depending on your particular model, there are some pincushion adjustments in the service mode. But it would probably not fix your problem,since it only appears when you use the video input.Can you post some pictures of the picushion effect when using the video input and then some from the standard TV input?What is your model number? It will say that on the rear of the set.Something like KV-27Sxx or KV-27Vxx,etc.

[similost]

Just a thought... I may be thinking too simple here, but... how close are your speakers?

You said it looked fine at the shop.. enviroment?

[Nakdoc]

Something doesn't add up here. You cannot have pincushion on video and not on RF.

[Gronkus]

it is a KV-27XBR55 Sony Trinitron XBR 1992 model. it bows in on each side in the middle area or the tv. The normal cable looks fine, but video 1,2 and 3 have the issue. There are no speakers close to it, as the speakers are detached from the TV entirely.

[Duane]

From your attached pictures, it doesn't look like the classic pincushion. It looks to me that the horizontal size is not correct.It looks like underscan. I'm surprised that the repair facility couldn't see this.I'm also at a loss as to why it's video input only. Are both pictures from a video source or is the first pic the TV mode?

Sonys have a service menu that can correct/adjust for geometry.You can increase the width of the picture and that might correct what you're seeing,but that adjustment is global across all inputs.I don't think this is the solution,however.

Can you state why the repair facility couldn't deal with this issue?

[Gronkus]

apparently they didnt take a look at the video inputs, but insead looked at regular coax ( catv ) input source. It makes no sense to me how his is happening. For example, when i turn on a system at first, it displays the name of the system wit a white background, which looks perfect, then once it loads further in to the next screen, that is when the image bows inward. also it looks like the picture is vibrating up and down on certain screens, and i can notice some kind of color bleed.

[andy]

000

[Trance88]

I've seen this happen with a few TV's. My 2002 RCA 25" Does this slightly on video input only but not to the extent you can see black outside the picture. With my TV, straight lines near the sides of the TV sometimes look slightly warped.

[gadget73]

The short answer is take it back. If you paid someone to fix the problem and it still exists, tell them the problem is not resolved and have them do the job they were paid to do.

[Duane]

Originally Posted by andy

It probably has the same problem from all inputs, but a video game system doesn't overscan as much as broadcast TV. It doesn't look that bad, so a small adjustment of the H size, and pin amp should fix it. A 1992 model might have adjustment pots for this.

I'm fairly certain that by '92 ,Sony sets had digital memory for adjusting the sub parameters.You either accessed the mode from the remote with keystrokes or you used a toothpick to push in a button from a small hole on the rear of the set.

[Gronkus]

yea the pinhole in the back throws the tv into service mode