TM 5-6675-316-14
(3) As the font disc rotates, the amplified signal picked up from the strobe
track is passed to the font interface logic board. Here the signal is compared with
a reference frequency generated by a master clock circuit. The difference of these
two frequencies is passed to the driver board, which modifies the supply to the font
drive motor until the two frequencies are identical.
h. Shutter solenoid. The film magazine assembly houses a shutter unit which
shuts off the magazine, and unexposed film from exposure to light when the covers or
doors of the main optical section are opened.
2-36
