I am currently using a Sansui 9090 db(1977, RCA plugs) & am in the process of connecting it to a Vizio LED flat screen. I don't how to get the receiver to output the sounds of the flat screen out of the audio system's speakers?

It worked with the old TV. I had a junction box with several RCA plug sets & was able to put my iPod through the system too.

I thought if I was able to connect to the available RCA plugs on the TV, I would get sound?

What am I doing wrong? What is different with these HDMI tvs that have some RCA capabilities?