Do you have The Aperture Installed? disable it.

I've never installed that mod, i disabled all other mods I had installed after i got jazztronauts but it still isnt working

Same! I'm having that problem too but I can't find any way to fix it. I uninstalled a few of my older mods that could've caused some conflicts, but as far as I'm concerned, the TV is still showing only static. It sucks, I really want to play this game too.

I managed to fix it by reloading the hub map using the command changelevel jazz_bar

i did find a work around this by typing changelevel (name of a map you want to select), it works as if you are going through the tv in the bar (altho, before you do the change level thing, do it when in the bar map first!)