This is a 8 year old TV. The picture shrinks into a line. It degresses over a few minutes. The sound is fine. Sometimes it is a few minutes sometimes it is a half hour. This has happened to two tvs in this area. They are powered through a surge protector.
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Re: Panasonic TV picture shrinks to a line
There is an IC which controls the vertical deflection and over the course of a few (or 8) years with the set heating up and cooling off some of the connections work their way loose causing the symptoms you describe. If you were to bang on the side of the set you could likely "pop" it back in but this is not a good solution. The vertical IC needs to be re-soldered. This is especially common in Panasonic sets. About 10 minutes with a soldering iron should have it worked out.
If you're handy with a soldering iron I can tell you what to look for.
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Since the set works initially, there are likely poor solder connections at the vertical IC. If this is not addressed soon, the IC will fail and need to be replaced. The vertical IC is a small flat IC with about 11 pins or so that may be marked LA7837 or something similar. Try resoldering the pins first. If that fails to resolve the problem, replace teh IC. Feel free to post the marking here so I can verify you have the correct one.
If the shrinkage is just the top & bottom then it is relatively easy/low cost fix. Most probably, a capacitor in the vertical section is nearing end of its life. This would be the biggest of the bunch and would be something like 47uF/50V.
If however, the shrinkage is on all four sides, then it is the master power supply that is at fault. Chances are the main B+ is getting low which cold be caused by the big filter capacitor or an erratic regulator. This is not a simple fix and would require the services of a qualified professional.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
All symptoms indicate a problem in the vertical circuit,the first thing to look for will be loose conection on the vertical output IC,sometimes this IC goes bad completly and it needs to be replaced.If you are familiar with soldering electronics you can take care of it but if you are not too familiar you can play it safe and take it to a servicer ,it will be a lot less expensive than if they come to your house.Let Us know how it goes or if you need more information.