I am currently dealing with the same issue on my 2018 Jayco. I also have the Razor. everything was fine and working on our last trip in the fall b4 the trailer was put away.
I tested all connections and tested for 12v at the booster. all checked out. After a bit of research and a few youtube vids i believe the unit is sealed and cant be taken apart or tested from the outside.
SO remove the 3 screws from the rotation knob on your ceiling and remove it. It will also have a keyed extension shaft you can pull out.
feel around in the hole and you can pull out your coax and the thin black cable wire from the Rayzer and you will see a connection.
unfasten your connection and test for 12v at the coax side. If you are getting power up to there then i can only conclude the attenna is shot.
If you search for some razor install videos (lots on youtube) you may get a better picture of what im trying to explain.
My TV reception went out all of a sudden like yours. I removed the antenna on roof (did not have to break sealant) and connector inside had come off. Re connected and all was good.
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2017 Grand Design 388M
2017 F350 DRW