The cable TV signal merges with the rooftop antenna signal at the Signal Booster in the bedroom. One output of the booster is to the bedroom TV. The other output feeds the rest of the TVs.
Check your pass through basement storage. If there's a coax connector there, that's the next stop after the Signal Booster. You can test that connection with a TV to see if the signal is getting there. If no signal, there may be a problem with the splitter behind the coax connector wall plate. Sometimes they're directional and the wires can be connected wrong. It's also possible the Signal Booster connection has a problem.
Careful working on the signal booster. It's easy to short the connectors to the power lead and blow a fuse.
After the basement, I think the coax goes to the living room. If the TV is in a slide out, look underneath for a barrel connector or junction box where a barrel connector may be hidden. Connectors can be loose.
There's also probably a splitter by the exterior TV. Another place to check.