TM 5-6675-316-14
(1) The shutter solenoid is connected to the actuating arm by a downlink
attached to the solenoid armature. The blade moves downward to uncover the shutter
area, and is held down by a 300 mA holding current. When the cover interlock switch
is deactivated, the blade is closed, sealing off the film from exposure to light.
The shutter solenoid receives its operating voltage of 26 V from the driver board.
controlled by the font interface III board.
(2) When the composing machine covers are closed, the optical assembly is
lightproof, interlock switch S1 is actuated and initiates a high, which turns on
Darlington Q34. Shutter solenoid switch S2 is in the normally closed position, and
allows the full 26 V to pass through the solenoid operating coil. This activates
the shutter. With the shutter fully open, S2 opens and the operating current passes
through the 7.5 ohms holding resistance dropping from the full 2 amps operating to
300 mA holding current. When the shutter solenoid is deenergized, any induced
voltage transients are shunted away from the Darlington Q34 by diodes CR2, CR3 and
Delay capacitor C7 is across Darlington Q34 to slow the
part of bridge CR16.
switching and suppress transient noise.
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