My Sony KV-27V36 had similar symptoms as mentioned in this thread. The picture disappeared from the bottom up to the top and sound was still good. Sometimes the picture would come back if the unit was turned off/on, but eventually it would lose picture again. (Made me feel bad for the kid who was scolded for doing this and killing the TV in a previous response) Here is how I fixed mine....
After reading all the replies in this forum, visually inspecting all boards for cold solder joints, blown parts, etc and researching the DIY fix-it kits online. I found that the power supply boards are relatively expensive ($100-200) and not available when you put in a request. The DIY kits are probably giving you more than you really need, and possibly omitting some you do need. They cost ~$40. At this point, I'm thinking it's not worth the time/energy to fix a TX that can be replaced for $300 new, but I wanted to take a shot with some of the easier fixes suggested here.
First, the entire inside was VERY dusty after 7-8 years of hard use. A can of compressed dust remover is needed to even see the components and remove the chance the dust is creating a thermal blanket.
Second, there was visible heat damage near Q601/Q602 and since these are part of the suggested replacements I thought this was the problem for sure. The most darkness on the PCB was actually under the ferrite bead parts (start with FB) But, if there is still sound and the outputs from the PS board are OK, then it is probably not the cause. To be safe, I pulled the transistors out of the circuit as well as the R607 and measured them. They all appeared OK, so I resoldered them back on.
Third, Q502 a horizontal output transistor was another common suspect and somebody suggested some cross reference replacements. Fry's happened to carry them so I picked one up for <$5. I pulled Q502 off and compared to the new one to find there was not much difference. I put the new one on anyway making sure to clean the heatsink well and use a good thermal grease. Many people probably skip out on this part which is why their fix is short lived. I had some extra thermal grease and cleaning solution from a CPU heatsink so it didn't cost me anything. While I was soldering on this board, I touched up the pins on an IC also mentioned in this forum although the joints looked good. I should also mention one of the heatsink pads looked like it may have been lifted a bit so I bridged solder to an adjacent connection - just in case.
I'm not sure which of these steps was the actual fix, but the TV has been working as well as ever for over two weeks now. Total cost = $5 transistor that probably wasn't bad, 1/2 can of dust-off, use of soldering rework equipment, leftover thermal grease from a CPU and some time/patience. All in all, it was actually a good learning experience.
Would I buy a Sony TV again? You bet. Their strength is superior video equipment in general. That's why you paid a few more bucks in the first place, right? (This is probably why they are focusing on LCD technologies where they can differentiate themselves more than plasma, etc. Plus, imagine the hate threads when those start to die!) This TV has been used hard. It started as a demo model, had years of preschool kids by my wife's home daycare, my kids, it has been moved several times, and finally became a good bedroom set - hopefully for a few more years.
Key learning: a can of dust remover across all my electrical components as part of spring cleaning is a must from now on.
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