I have a problem when watching DVDs on my Onkyo TX-DS575X Receiver and Onkyo DV-C501 DVD player. Every once in a while, while watching a movie, I hear an audio dropout. It happens at least one time on every one of my discs, not just a select few. I wonder if the lens needs to be cleaned on the DVD player or if it's a problem with the receiver. I've had the receiver and DVD player since summer 2000. I've never had the components cleaned or maintained. They've played fine up until recently. Any help would be appreciated.