Just a quick update for anyone having video problems with the Samsung Series 7 LED big screens - FINALLY found the source of my problem and FIXED this beautiful TV! Frankly, was just about ready to junk it after replacing the sub-power asy (typically a high fault rate component due to bad capacitors) and also the main DMD board (recommended by Samsung tech, although he didn't do much troubleshooting). Had pretty much given up hope but decided to give it one last chance... Turns out I was able to pull the entire light engine out without much difficulty, confirm the 3 LEDs (red, blue, & green) were all good by simply touching a 9-volt batt to the top of each one, which then pretty much narrowed the problem down to the actual LED driver board itself. Ordered a used board thru eBay ($67) and EUREKA! Problem solved! This TV has one of the best pictures I've ever seen and it's wonderful to have it working again!