Funny this just happened to me today earlier this morning. My problem was I have only 1 antenna, and 2 receivers. I forgot to bring the antenna out of my bedroom into the living room. And I actually have this reversed, it was my Onkyo receiver that was behaving like yours, because my Yamaha HTR-5935 in my bedroom had the antenna connected. Had to turn it up all the way to MAX volume before I could hear anything, and I knew that wasn't correct, so if you have an antenna connected, check to be sure it isnt cut or broken, make sure you're getting a tight fit on the socket, and be sure it is raised as high as it can be