Just wanted to update a problem I wrote about a few months ago and describe my experience with LG Tech Support.
For a while now my set had one zone in the upper-right corner that stayed slightly dimmer than all of the other zones on the tv. It was not that noticeable most of the time, but anytime there was a shot of a sky, or any other single color, it was very noticeable. The zone was dim all of the time no matter what input was in use.
Also, whenever I finished viewing something via USB and switched back to cable the entire screen would brighter than it should be. This did not happen every single time I switched from USB to cable, but it did happen most times. The only remedy for this was to turn the TV off and on again. This problem happened the entire time I have had the television.
I called LG and described my problems. The woman was very professional and had me reset the TV (Unplug and hold power button for 30 seconds). This, of course did not work. She then set-up an appointment for a tech to come to my house.
The tech called about a half-hour before coming over. He was on time, professional, courteous, but did not seem extremely knowledgeable. I told him about the problems, he looked at the tv and immediately saw the dim zone. He told me he would call LG and see if they could get him a new panel for replacement. He said he had never seen this before and that he had never heard of the problem I had with switching from USB to cable. He told me he would look into that and get back to me about it and about the panel replacement.
He called back about two days later and said he was waiting for an answer from LG about getting the panel replaced and that he would get back to me when he got an answer. About a day or so later he called back and said a panel was being sent to him and he would call me when it got it so we could set-up a time for him to replace it. It took a few more days for him to get the panel and he called me and we set up an appointment for replacement.
When he came over to replace the panel he said that he could not find-out anything concerning my USB problem, but said he would put a new main-board in it, which he did. Panel and main-board replacement took a little less than an hour. Again he was prompt, courteous, and professional.
This was about a week ago and I am very happy with the results. No dim zone and tv behaves well when switching from USB to cable. This panel seems a little more clear as well. I noticed some "dirty screen" when watching hockey on the old panel - this one seems to have very little. Did lose my picture settings, but I needed to re-do them with a new panel anyway. Also, my old TV had firmware 3.13 and this main-board has 3.17. I do not have my TV hooked-up to any type of sound system.