no picture just sound

I have a pioneer DVD RW tivo basic... everything worked fine for about a week, now I only get sound, and no picture....does anyone know why? I have our Tivo hooked up in our theater room, and we have a tv upstairs, that has a connection that goes from the theater room to the tv upstairs, so we can view the same picture. But it worked fine for awhile.. just not sure why it isn't now.

thanks for any advice..

musicgirl