An improved currency validator apparatus adaptable to be assembled in either a validator up-stacker, down-stacker, or stacker-less configuration is disclosed. A motor bracket housing and an optics housing interconnect to form a bill passageway. The housings contain optical and magnetic sensors, permit the easy re-positioning of a magnetic sensor and an opposing pinch roller assembly, and preferably are made of a translucent red plastic material. The red plastic material permits the unobstructed transmission of infra-red light from an infra-red sensor, and further acts to indicate the position of the banknote entryway when illuminated by the optical sensors. An improved pinch roller assembly which automatically adjusts to the way in which the magnetic sensor is seated is also described. Further, an encoder positioned on the motor drive shaft, and accompanying slotted optical sensor, provide greater accuracy regarding bill position in the validator.