Apologies if this question has been answered before but as I novice some of the technical terms mean nothing to me. I have had the 4300 for a couple of years now and have been very happy except for an issue with the speakers. On occasions, I appear to "lose" one of the speakers. If I wiggle all the cables or move the 4200, the speaker comes back. Do you think it is just a loose connection at the terminal plug or something more serious? Any comment most welcome.