I have read all of the issues that vizio has had on backlight issues. My 55 in has power and sound, and the picture is there, but it is almost black. If you go up real close to the screen, you can see the images but barely. From a far, it looks black. I have read that you can just replace the board to fix, but I'm not sure which board it is I need to replace. Is it the PC board or the main board? Please help... Thanks!