I have said it many times.. Many RVers have a few screws loose... The mounting screws.
Also check behind it there may have been a cable come loose..
On mine one function did not work properly.. Turns out the 10-t installer plugged a cable into the wrong port.. Moved it. all good. What's a 10-t.. First name 1 Middle name D last name 10-T.
YOu have a CRT system or flat. Either way need to check you screws that hold that part of the cabinet together and tighten them up. Ensure you put some glue or locktite on the threads when you tighten them back up except on the back of the TV if Flat screen. You want to be able to take them out when have to change the TV out.