The volume control on one of my Sansui QS-800s has gone bad (mechanically) and locked up. Potentiometers can do that when they get old. The control is a bit unique as it is 4 potentiometers (one for each channel) ganged one behind the other on one pole. Anyone out there know where I can find a replacement or have a dead QS-800, QS-800A or QS-500 they would be willing to part out? (I am sure the same control is also used in the Sansui QS-800A and more common QS-500 models.)