Never thought it would happen to me but I have the LN46A650 and one day I come to turn it on and viola! no picture from my standard cable source. Sound works fine, just no picture and I can switch sources also, the backlight is working fine and there is no turning off and on like some are plagued with. I have concluded that it is the T-con board which is the other problem many experience from my avid searching of the internet.
I am technically adept at things like this, so I repaired the unit myself and will give my honest thoughts on what I think of Samsung to review sites and people I know. This television has been used by one person in a climate-controlled environment and came to me not long after they came out in a box that looked great without damage. (The first one also came to me undamaged box but had vertical lines on the screen, and we won't get into that freight returning deal but I still was persistent on this tv).
As far as picture and new technology I will give sam a thumbs up in that area. Although, there needs to be better quality testing and STRESSING in there factory if any at all. As I have read they have made changes to the location of this board that heats up too much due to lack of heatsinks and/or fan and is now located below the power supply which creates better cooling. I added my own heatsinks to the chips that heat up due to thick thermal pads attached to a tin cover, that is there idea of saving money and saying "yeah that's good enough, lets just make it a little while past warranty".
Yeah, and you know what, I was 3 month past the Samsung's 3-month extension warranty. I also sent in a repair request just to see what would happen and Sammy never called, OH, but I did get a call from a repair place out in Utah about a 1,000 miles away. I was so good about registering online as soon as I got it too. I think I got took. My future purchases and recommendations to people will be going to more reliable brands.
Btw, for those that do have a sammy (last years model or older) I suggest you turn off Noise Reduction, DNIE, and Dynamic mode. These modes have been linked by others on AV forums to cause more stress on this board and its chips. I also read something about a patch update on this tv possibly causing problems with 120hz. All I know is 120hz was toned down in a software update, hmm I wander why?
I would say from what I found on the internet there is twice, if not triple the amount of people having the same problems (power supply, T con boards) that don't use or post on the internet but I wanted to give my personal thoughts on the experience on my investment on a tv that should stand the test of time. Or at least more than a YEAR AND A HALF!
p.s. Look up Samsung t-con boards on sale sites like Ebay, LOL