Abstract: A positioner apparatus for moving a transducer head from one to another of a number of parallel tracks extending lengthwise along a recording tape, including a rotary cam with surfaces defining an inclined plane, a cam follower for riding upon such surfaces, a transducer carrier or mount coupled to the cam follower, and guides along which the head carrier is moved by the cam and follower and which serves to index the transducer head at a number of mutually spaced but generally parallel positions extending transversely across the width of the recording tape. Preferably, the rotary cam comprises a wheel-like member having an annular recess around its outermost periphery, with the edges of such recess defining a pair of complementary, spaced, curved ramp surfaces whose path of curvature is concentric with that of the wheel-like member itself.