Pioneer radio---no AM/FM reception.

I recently and very happily took delivery a new 2014 airstream 30 ft. Flying Cloud. I'm having a problem with the Pioneer radio. Simply put, I have no AM/FM reception. I've made certain the Local/Distance switch is in the off position(and tried all other positions as well) and the radio is otherwise properly set up. I've also made certain that the roof top antenna is securely in place. In order to determine if the antenna was properly connected to the radio, I attempted to remove the radio from it's housing. I successfully removed the faceplate but cannot seem to figure out how to remove the radio trim ring. I believe this is necessary in order to use the supplied keys to remove the radio and check the connections. I really hate to tow the Stream back to the dealer but will do so if necessary. I know the Pioneer system is new to airstream but was wondering if anyone has had a similar problem or could offer any helpful thoughts. Thanks.