Well, my 19 month old SV421XVT LCD HDTV just bit the dust today. Up until now, it's been pretty much a flawless performer.
We had Meet the Press on this morning and after about 30 to 45 minutes, the HD picture quality took a major dump, with super graininess, distortion, pixelation up the wazoo, and generally weird colors.
I turned off my 421 and Dish HD DVR satellite box. I checked all connections & cables to/from my 421. I then reset the 421 picture quality to factory default settings. I then swapped in new HDMI cables. Finally, I played a Blu-Ray in my BD70V player. Unfortunately, none of the above did anything to improve the extremely low definition and distorted image quality seen on my 421 (although the process eliminated everything else and directly implicated my 421).
Interestingly, we find that if we leave the 421 off for about an hour and then turn it back on, the HD picture quality comes right back. However, about 1/2 hour later, the picture quality takes a dump again. So, whatever it is, it appears to be heat dependent. Additionally, anything in black & white (like movie credits), are crystal clear.
Luckily, we have a 4-year warranty through Square Trade, so I have initiated a claim. Trouble is, we live out in the middle of nowhere, so it likely means that we have a very long drive ahead of us to a distant repair center or a pricy shipping bill.