I have been reading this thread for about a week now.
I was gifted a Samsung PN58C680 that had the pink banding issue.....after some reading and finding the Samsung service bulletin... I broke out the trusty Multi Meter and adjusted the VS voltage from the current 200VDC up to the recommended 213VDC....Panel is fixed.
Hardest part of the whole process was removing the 20 screws and reinstalling them.
I do recommend you have a couple extra hands to hold the panel upright...