I have the same problem,with UA50BU8000W, but i noticed something different?
When I unplug the ribbon between the two LCD boards, it stops cycling, and does not show a picture like everyone else.
But when i plug the ribbon back while the TV is still on!, The TV works normaly every time? with perfect picture and no tape on ribbon needed,
Its not a fix, when i turn the TV off i have to repeat, but i can see the TV functions normaly if you bypass the booting process?..

Hi, I'm a beginner with fixing TVs, i found a few broken TVs in my area and tried watching videos on YouTube to try to fix them, so far i have fixed 2 Samsung TVs by replacing the standby or startup capacitors, i have also used the sticky tape trick to fix another 2 TVs, i have many that confuse me thought, still learning slowly, i was reading these forums for a while before i signed up to ask anyone with more experience than me about issues when I'm confused.. I'm from Australia..