Make sure that the machine is disconnected from the power source. Check the drive belt to make sure that it is intact. Check the electric motor, most common fault is worn motor brushes, tilt machine and give the motor a fairly sound thump with the wooden end of a a hammer, or plastic handled screwdriver. NOTE HANDLE END. sometime this is enough to reset the brushes and prove the problem. If this gets it going then you will have to clean the commutator and replace the brushes.