U.S. Patent No. 3,498,570 - 03/03/1970 - Max Scholfield
Comments Concerning the Patent Gerald Stanley 03/03/2003: "Max Scholfield was my first boss and I worked on the implementation of this design shortly after coming to Crown. DC differential breaking is used on the reel motors for good tape handling. The trick was in selecting the right light bulbs for the differential resistance element."