I just bought a 570 that had the 'no fire' problem and it turned out to be the idler gear in the winding train was binding and wouldn't allow the winding ratchet to fully return when you released the cocking lever.
The screw, a phillips head next to the white gear, had loosened and the gear had no clearance and was binding the gear train. Simply moved the white gear away slightly from the blue gear and tightened the screw.
BTW, this is under the bottom plate. Four phillips screws and you're there.
Last edited by Fred Aspen; 10-03-2011 at 04:52 PM. Click to view previous post history.