46" vizio lcd tv

I have a 46" Vizio LCD when i turn the tv on i get sound but no picture. i was going to repair it but not sure what the problem might be?

It might be that the fluorescent backlight bulb has burned out or its power supply is faulty.

As audioguru stated...... try this: in a room with no lights on, in the dark, power on the set and take note if you observe a dim glow from the LCD panel. If you can see a faint glow (or obvious glowing dark gray screen) the backlight lamps and the inverter circuitry are likely working OK. You may have a problem in the video processing section instead. If the LCD panel is dark black (as when it's powered off) then I'd suspect the lamp inverter board first, and then the lamp(s) secondly. Most lamps seem to outlast the inverter circuitry, hence why that would be suspect #1. Some inverter boards have a fuse on them that could have opened for one of more number of reasons.

Presumably this is a cheap junk make?, as such they have VERY short life spans, and poor reliability. A common problem with them is failure of the inverter transformers.