Hi,I purchased a complete Aperion sound system in feb 05.  It included a subwoofer 651-S10 and a AVR635 Harmon Kardon Receiver.  For a few months now the subwoofer has not been working.  The sub's power is set on auto and it turns on when the Harmon is turned on.  In addition, when I did a system sound check on all speakers the sound I heard on the subwoofer was barely audible.  I'm not a techie but I assume there is a signal coming through but no subwoofer/bass sound.  Please help and Thanks