I have a Vizio Xvt553sv and on the screen towards the lower right I get a constant flickering. At different times in rectangle type box shapes around the screen the screen dims in those few areas. I had someone come out and look at it and they said the backlight was going out and that it would be better spent getting a new tv. I'm not sure if it is the backlight inverter or are their tubes in this tv that have gone out. Please help!
It does, I've played with it, turning it on and off and it doesn't seem to do anything. Last night, for instance, a white screen had come up on one of the programs and it looked as though there were multiple, square/rectangle darker looking boxes around the screen. Some were dark, some we're the normal brightness. Is it possibly the LED backlight inverter or is the panel itself bad? Oh, and it always flickers at the bottom right now in about at 1' x 2' rectangle. Not to black but it's like somebody's turning on and off a light switch really fast but it's a dimming flicker.
The inverter in older sets was used to create the high ac voltage needed to run the tube backlighting. You have LEDs which don't need the high voltage so no inverter board for you. You may have a backlight driver if its not integrated into the usual power board.
It definitely sounds like the backlight LED matrix or the controller.
edit - doing some checking on the internet it seems that parts are scare and vizio is saying the set isn't economically repairable so your tech just may be right.