I'm having a similar issue with my new UN60D8000. There is a dim strip in the top right corner. Did you get an explanation for the issue you are having?
The TV was purchased in July of 2011 its the new 55" LED 8000 series.
A few weeks back my wife reported that there seemed to be a darker part
of screen on very top.
We hadnt seen it again till yesterday when the top 1/2 of the screen
looked darker and distorted in top right corner. It happened at end of
day so I just turned it off.
This morning after about 1 hour of being on we noticed it again. In
attempt to test if it was issue with STB or TV I tried TV input same
issue and tried the blue ray player. The TV could not find the Blu
Ray player. I decided to try moving the blu ray to a different HDMI and
finally got the blu ray to be recognized and the TV seemed to be
working just fine. I have called for service but they werent helpful
and they said unless the see the issue there isnt much they can do.
Now I am noticing that the bottom 1/8 is getting darker and than moves
up to about 1/4 the display. Also noticing flickering of the Video.
Any ideas I have upgraded firmware etc. Should I just take it back??