Polaroid 636 Repair Manual page 16

15. In a low-light FAR picture, the blades open fully and the photocell sees scene light
through the photopic filter. When 100% of the necessary light is seen or when the internal
clock reaches 396 ms, the flash is quenched and the shutter blades close.
16. After the blades close, the motor is turned on. The timing gear advances the pick, indexes
the counter, and brings the S5 actuator back to its original position. The shutter system is
latched closed, ending the low-ambient FAR sequence.
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