It sounds like an improperly installed cable connector or pass through. On our unit there are two; one in the lower refrigerator compartment, and one inside the ceiling crank. In my case, the pass through in the ceiling crank had the center wire shorted. But the aforementioned relate to using the powered roof TV antenna. When using a cable source, make sure the antenna power button located on the connection face plate is turned off.
Here is more information that may prove helpful:
http://www.trailmanorowners.com/foru...ght=tv+antenna
Let us know what you find and how your issue is resolved.
Dick