Did you check to see the status of the amplifier? There should be small black button where your TV plugs into the antenna and a small light which is either on or off. Make sure both match (either on or off) between the TV that works and the TV that doesn't.
2013 Jayco JayFlight 26RKS
2013 Ford F150 Ecoboost FX4
2003 Coleman Bayside / 2011 Jayco Jayfeather X20E -- RIP
2012 Tacoma Sport DCSB / 2013 Tundra SR5 - RIP