It sounds like you have a short somewhere in the coax cable or at a connector. Start with this thread:
http://www.trailmanorowners.com/foru...hlight=antenna
We bought our unit from a private party (in 2004). The first time I tried the amplified Winegard antenna the reception was skimpy. Pushing on the amplified button resulted in no reception at all. Turning off the power button brought the station back in, if only marginally. I finally traced the problem to the pass through connector located at the base of the antenna hand crank. The coax cable running up to the antenna had the center wire insulation stripped completely off allowing it to short out. I think the installer must've realized the mistake because the wire had some clear silicone wrapped around it. Over time the silicone worked itself loose.
If you need more information send me a PM.