I have a purity problem with my 36" JVC HDTV I noticed months ago that i have purity problems in the corners of my tv. But in the last day or two, I have noticed that I can get it to look pretty good for a minute, then if i turn tv off for a few minutes or so, it looks bad again. i have moved my front speakers out farther away and have taken my center channel speaker off tv and moved my sub further away also. Why does it change after a few minutes or whatever? i am gonna look in my manual and see if my extended warranty covers this problem and maybe i can get it looked at.....would the place i bought it at have a technician? I bought it at an appliance, electronic store.