Help - I have a Beosystem 4500 running Beolab 5000's (upstairs) and 3000's (downstairs through a Master Control Link 2).  The Audio on the downstairs speakers suddenly stopped working?  The remote control and digial readout on the speakers work fine - but no audio?  Anybody ever had this happen?  I had the MCL2 inspected by a B&O service center and it checked out fine.