I have a 47 inch Vizio m470sv TV with no sound. I think the main board controls the audio, but I think I need a service manual to be sure, and see what's involved in replacing it.

Are you sure matched on the right video input to the input you are plugged into on the back?

Most likely it's a capacitor fault.

Google "Capacitor bulge" and then search Youtube for your make and model to see if anyone has done an instructional video. You'll need to be comfortable dismantling the TV and be able to use a soldering iron. If this isn't you then take it to a repair shop.

Contact the authorized dealer to get more details. Gopakumar Gopalan Google

Are you on cable, or streaming? may be the source (box) try to run a DVD see if you get same issue if yes than tv if not its source. Vizio do not ssay please wait source may be buffering.

i am having the same problem and my power light wont even turn on so i think it might be tht power fuse. Is tht what was wrong with urs?

Sounds like you had a high voltage power surge just before going out
Are u using a high grade reference center or surge stage 2 or 3?

Go into ur tv Menu goto OPTION go down to Output Select,press enter make sure selection on (Fixed).This fixed selection will pick for the tv out put to tv speaker.Tv should have sound now on it speakers.Try website like Remotes.com to buy the tv original remote work for the best used for to reajustment setting and setting on the tv Menu.

This sounds like a main board issue to me.

my vizio made a popping noise and then screen went black. tv has power

Yes, changing the main board should correct the problem.