There should be a small black connector with two grey / black wires on it coming from the turntable. This plugs into the back of the tuner / amp unit. You will see it just below the two phono plugs (With an LBT-D105 model) also from the turntable. If it is connected, then there could be three problems here why your turntable is not rotating. First it could be a faulty start/stop switch when you que the arm to play the record, or it could be that the belt has come off the motor pulley that turns the platter. And thirdly it could be a faulty DC motor. However it would be very unlikely that the motor would go faulty. Good luck and hope you get it fixed!
hookie, August 2014