No sound when using dvd or playstation on aux...

We have this emerson tv/vcr combo, we have had a dvd player and at times a Playstation One hooked up to it using the front input jacks. The TV must be on AUX channel to work, now when we tune to that channel there is a hum in the channel, and there is no sound from the device that has been input. We do have a picture for the PS one, but not the DVD. Anything we can fix? I hope so, this is our second one of these tv's! Ironic this just all of the sudden happened? And I JUST threw away the receipt (we bought two years ago for Christmas)!