The tone arm is still connected to the base of the turntable by several wires.

The audio cables from the tone arm pass through a plastic stress relief collar where they exit the case. Pull this stress relief collar out of its slot in the case bottom.

Remove the screw securing the grounding wire to the large circuit board. Put the screw back in the hole in the circuit board, so it doesn't get lost.

After detaching these wires, the tone arm assembly comes free from the base of the turntable.