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7. When the slide latch is
tripped.
the cocking slide
2.
The mechanical action, of aU the Shutters
releases; as the cocking slide returns to its rest
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position, a roller contacts a tang on the blade
latch. and forces the blade latch down (Fig.
l~).
This action, first: releases the opening blade,
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and it snaps into position, aUowing light to pass
through, exposing the film; secondly, pennits
the blade latch to open switch 52. Opening 52
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initiates the electronic measurement of the
amount of light and time to which the film is
being exposed. The photocell uses the average
scene light to control the: flow of current through
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the liming circuit.
When the
proper time, de
pending on fUm selected, and aperture size, has
elapsed. the magnet current is cut off. ThiS re
leases the closing blade, which rapidly snaps back.
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and shuts off the light, completing the
mm
exposure.
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8. The above action also fires the flash gun when
(ine is used_ The combination (Fig. lw2) of
X~
-
make.
X~break., X~contact,
X--connecter, and
Rash saft':ty switches controls the firing of the
flam.
B.
ELECTRICAL ACTION
I, Electrical action is initiated. controlled, timed,
-
and terminated by the Electronic Module sub
assembly of the shutter. Mechanical action.
as previously described. is part of the overall
electromechanical action_ Switches must first
be opened or dosed in predetermined sequence
in order to start the electric circuits functioning.
3
concerned here,
is
virtually identical. The ele<?
tneal action is aiso the same as far as basic
pur~
pose is concerned: the time and quantity
mea~
surements of light. But increasing
sophistica~
tion of design, and employment of miniaturized
components, has led to the developmenl of
many different electronic modules.
3. Electrical action will be described in detail with
respect to the ultimate purpose of the circuitry,
but without concentration on the specifiC uses
of components. The following section (Section
Ill)
wiJl
present detailed information. including
identification, and sufficient other data. to
per~
mit field use of any Electronic Modules stOCked.
This contributes to economical. customer repairs,
4. The basic eJectronic circuit is a two (2) rransistor
trigger: it uses a photocell to control the length
of time that a small electromagnet is energized
(Fig. 1-5). Power for the circuit illustrated (Fig. !
w
7)
is obtained from a 4.5 volt bauery. Later modules
use a 3 vol t type power source.
5. Electrical action requires the closing of switches;
S2
Grst~
and then, S
1.
the battery power switch,
51 is closed by pressing the shutter release button.
When SI operates, power is applied simultaneous
ly to two (2) circuits: 1) the electromagnet hold
ing circuit, and 2) the capacitor by-pass circuit.
In the first circuit, current flows from the battery
(Schematic Fig. 1-7) through SI to one terminal
of the coil of the electromagnet M. and through
RI to the base of transistor Q2.
As the volta&e on the base of Q2 increases, the
NPN transistor turns on, because Emitter to
Base electronic current flow begins.
With
Q2
"on", current now flows through the coil of the
magnet M, completing this circuit and holding
the closing shutter blade OPEN. See diagram.
Fig.. 1-8. for a representation of the described
current now_
In the by-pass circuit, current flows (Ft" 1-9)
from the battery. through S I. photocelJ LDR.
re
sistor R6, and S2, to the other side of the battery.
This completes this cjrcuit. and by-passes the
com~
ponents noted on Fig. 1-9, just sO long as S2
re
mains clOsed.
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