Most techs figure 5 years on sets today. Can be upsetting.
According my experience plus some research points to connections or drive board problems. Parts are over at samsungparts.com (service manuals too) and shopjimmy.com
Watch the video! -> https://www.youtube.com/watch?v=h4XWCxUsSVU
My TV has exceeded the warranty but short later we have seen a horizontal thin black line on the screen .. any Idea what it could be.. I am planning to buy new TV .. shall I go with Samsung any more?!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic