Abstract: A two stage motorized servo-actuator having a worm driven high reduction gear train providing a rotary output. The motor shaft has a worm and co-axially therewith, a beveled pinion. The motor worm is continuously engaged with a first stage gear. The first stage gear has an input sector gear disposed co-axially and rotatable therewith. The input sector gear intermittently engages an output gear. The output gear has a beveled output sector gear disposed co-axially and rotatably therewith. Upon disengagement of the input sector gear with the output gear, the beveled pinion engages the beveled output sector gear to drive the output gear directly. Once the input sector gear is disengaged from the output gear, a return spring on the output gear can reverse drive the motor through the beveled pinion to return the output gear to a desired position in the event of motor failure in operation.