I discovered something in our Roo 23IKSS that may apply here. If you have a disconnect switch (ours is mounted under our LP tanks), look for a yellow wire attached to the battery side of the disconnect switch. On our Roo, that is the wire that powers the radio. Follow the wire for a little bit and you may find an in-line auto-type fuse. Check to see if that fuse has blown.
I guess FR wired ours that way so turning-off the disconnect switch did not power-off the radio and cause the station presets to be lost.
Theo & Carol
2007 GoldenDoodle ("Cooper")
2020 Rockwood Roo 23IKSS
2015 F-150 4WD XLT SCab, 5.0L, 3.73, 36gal, HD Towing Pkg (53A), 1,980lb Payload