One day the sound is working the next day it isn't.

It is connected from the back of the TV to a satellite on the roof.
This is were the channels come from.

Those TV's have a problem with the headphone plug where the little reed switch on the plug outlet is located and it either sticks or gets dirt in it, which cuts off the sound. When you plug in a set of headphones it turns off the sound. Test it out by plugging in a set of headphones to see if it is the problem. If you can spray a little contact cleaner in it and plug and unplug a headphone plug a few times it may clear it up. Otherwise, you will have to remove enough screws to be able to get to the plug outlet and clean the reed switch on it, which is just a strip of metal that bends when a plug is inserted to break contact to turn off the speaker.