Hi everyone. This is my first post here but I've been reading posts on AVS for over 3 years. Thanks to everyone for all the great info. Please forgive the length of this post. I hope you find it informative.
A tech was here 2 days ago to replace the bezel on my 46-inch A750 (more on that below). The tech mentioned that they've repaired a number of older A750s having power supply capacitor problems (entire PS Module is replaced). He pointed out that it's generally two large caps on the PS board that fail. He said that the voltage rating for the installed caps was too low (confirming what others have already posted here). Generally, a failing cap swells or bursts open due to heat build-up and then fails quickly afterwards.
To replace the bezel, the entire case had to be removed. While the case was off, the tech peeked inside the power supply module and noted that the caps still looked perfect (I took a peek as well and saw no bulging or leakage). For the record, I purchased my set in Dec-08 from big river and it was manufactured in July-08. My warranty (12+3 months) is up in March. The tech told me that if the PS needed to be replaced out of warranty that the total cost would come to around $350 including labor.
I opened a repair ticket with Samsung under the guise of fixing the so-called halo effect. However, I never personally considered the halo-effect to be a true defect (just a very odd design quirk) and to be honest, the effect never bothered me. The wife and I are extremely happy with the performance of this set.
Two other bezel problems are what really bothered me... First was the TOC delamination problems which plague the A750s. My set had no delamination when I received it but within about 4 months, it was visible on close inspection in several spots. By 10 months it was just becoming noticeable from 9 feet away. Second, the upper-right and upper-left corners of the bezel were beginning to separate and warp away from the main cabinet shell of the set. You could pull (very lightly of course) on either corner and easily notice about an eighth-inch of play between the bezel and the cabinet shell. The tightness of the cabinet screws had no lasting effect on this... you could snug them down and within a few minutes the bezel would pop back out. The original tech who came out to verify my halo effect claim, said that he had seen cabinet shell/bezel separation on a lot of sets (in fact he pointed this out to me almost right away, before I had the chance to show it to him).
The new bezel fits snugly to the cabinet shell and has zero delamination issues. I compared the edge of the TOC on the new bezel vs. the old bezel and the new bezel now has a slight ridge bordering the edge where the red TOC laminate ends and the clear portion begins. It almost looks like the edge of the TOC laminate is embedded within the ridge.
Also, the halo effect was almost completely eliminated. With the old bezel, anything bright at the edges of the display was easily transmitted through to the outer edges of the bezel (for example, the light/dark areas in verbage in the crawling text displays on the news channels could be easily seen in daylight when positioned within 5 or 6 degrees of center at a distance of 9 feet). With the new bezel the effect is much dimmer (only slightly visible in total darkness) and the viewing angle where it is noticeable is now very narrow (perhaps only 2 or 3 degrees from center). But like I mentioned earlier, the halo effect wasn't my issue... my real goal was to get the TOC delamination and the bezel/cabinet shell separation problems fixed before my warranty was up.
One more thing... I now have a better understanding of why the back-firing woofers in this set sound kind of lame! With the cabinet removed, I could see that each is barely 2-1/2 or 3-inches in diameter and each is mounted in a small plastic resonant enclosure (given all the open space surrounding each of the enclosures you'd think they could have designed something better).
Overall, I am extremely happy with my A750, with Samsung's support, and with the turn-around time for this fix. I opened the repair ticket in mid December, a tech arrived 1 week later to verify the problem, and another tech arrived about 3 weeks later with the new bezel (exactly 4 weeks from initial call to fix).