With the belt off, does the machine cycle (does the needle move) when you turn the hand wheel by hand? With the belt off and the clutch knob (the small silver colored knob inside the hand wheel) tightened (clutch knob turned clockwise until tight), the machine should spin freely, for me this means I can give it a whirl by hand and achieve several complete cycles of the machine (with the presser foot up so there's no friction at the feed dogs).