You might want to check the coax splitter behind the panel. I had thus same problem and found the cables were all loose. Also, the black switching was bad so I replaced it with one that has inputs for cable, tv, aux1 aux2 and RGB and outputs for all 3 TV's, now I can view cable on one tv while viewing a movie on CD on another. Its no longer one connection for all TV's. Bought it on Amazon
5 input, 3 Output Video Switching Center Accept 5 inputs: TV antenna, DVD, satellite
https://www.amazon.com/dp/B00SWGSESO?ref=yo_pop_ma_swf
You will need to remove the splitter and bring all of the cables to the switching.......