My screen is black but the sound is on

sicahaze3  …. vizio tvs have a real problem with burning out their main boards. before ordering one, youll want to check some basic things. (youll require a multimeter and the knowledge of usage for most of these)

with your tv on and sound on, your main function of the power supply is functioning. the things to test on the power supply would be the backlight circuit. are the leds being fed proper voltage? do you see the backlights on through the back of the set?

if not, need to check the screen with a flashlight and see if you have an image. hold the flashlight close to the screen at an angle and hit the menu button and check if you see any image. if you have backlights, the next thing to check would be the tcon board.

there is a fuse on the tcon board right near where the lvds cable inserts from the main board. do you have 12v?

if so, youll want to do a panel check. disconnect power from the set, remove one ribbon cable from the tcon board that leads to the panels buffer boards. disconnect one (leave the other connected), reapply power, check for black or white screen on side thats disconnected. do the other side the same way. if there are any lines on screen at any point, your panel has failed.

with these tests, its just a quick easy way to rule out components/boards other than the main board.

if there are no backlights, youll want to check your power supply board for the blon (or on/off) for proper voltage as well as dim. if these are not present or doesnt match the legend printed on the powersupply, its your main board.

if there is not 12v on your tcon board, your main board is not sending voltage through.

start with this and report back with your findings. this should pinpoint where to hone in and continue troubleshooting. when reporting back, also upload pics of your wiring in back so we can see what you do.