TM 11-6720-242-35
age which is derived from the scaling network (fig. 2-1).
c. When the emitter output of power transistor Q1
The output of amplifier AR1 (fig. 2-7) is applied to the
is excessive, transistor Q11 is partially turner on and the
base of a transistor in the temperature controlled
current feedback cuts down the ac celebration of motor
differential pair AR2. This turns on the transistor and
B1.
charges capacitor C3. Capacitor' C3 converts the signal
d. Scan cycling control centers in the operation of
to a sawtooth waveform which is applied to relay K2.
scan control relay K1. The relay coil receive an input of
The output of injunction transistor Q2 taken at B1 is a
+22 vdc interlock as long as there i film in the camera.
pulse approximately 50 milliseconds wide (fig. 2-8).
However, the relay remain deenergized until the scan
This pulse is applied to the base of transistor Q1, which
control signal is ap plied to transistor Q10. This occurs
applies it to the scan control circuit.
when oper ate relay K2 (fig. 6-11) is energized. The
scale control signal causes transistor Q9 to conduct
2-12. Functioning of Fail Safe Signal and
connecting K1 to ground. When energized, scale
Frames Remaining Circuits
control relay K1 (fig. 6-16) applies the error: voltage
output of amplifier AR1 to transistor: chopper Q6. When
the relay is deenergized (scale control signal not applied
a. The function of the fail safe signal is to provide
to Q10) a negative voltage is applied to the chopper
a pulse which will illuminate the OPERATE lamp DS2 in
circuit, cutting it off.
synchronism with each advance of a frame of film. It
e. When the OPERATE switch is set to OFI to stop
also stops camera operation and keeps the OPERATE
the camera action, operate relay K2 (fig 6-14) is
lamp illuminated steadily when the end of film has been
deenergized. Relay K2 then connects capacitor C1 to
reached or if film breakage occurs.
The circuit
the base of transistor Q10 (fig 6-16). Capacitor C1
generating the pulse also actuates the frames remaining
discharges causing Q10 t( conduct and hold the scan
mechanism and provides the input for the annotation
control relay K1 energized, keeping the output of scan
pulse circuit. The end of film switch, 1AlS1, located in
amplifier AR: to the base of transistor Q10 (which is
the aec assembly (fig. 3-3 (3)) initiates the fail safe
normally conducting) of the dynamic brake circuit.
signal which keeps the OPERATE lamp illuminated.
Simul taneously, operate relay K1 (fig.
6-16) is
b. The rotating timing cam actuates the puck
deenergized, removing the V/H input from amplifier
switch 1Si which makes a closure to ground for each
AR1. Thus, at this point, the output of amplifier AR1
camera cycle (fig. 2-6). This closure to ground turns off
transistor Q1 and causes emitter follower Q2 to turn on,
feedback from scan motor B1. The, decrease in the
which causes the control panel OPERATE lamp to
voltage applied to Q12 causes i' to cut off. With Q12
illuminate once for each closure of the puck switch. The
cut off, Q13 conducts an( the output of bridge rectifier
FRAMES REMAINING indicator is actuated in
CR1 through CR4 i, effectively grounded, stopping the
synchronism with the illumination of the OPERATE lamp
scan motor When scan control relay K1 deenergized, a
and counts down one digit for each closure of the puck
negative voltage is applied to the chopper circuit, cut
switch.
ting it off.
(1) The +22 vdc regulated voltage is
f. The scan motor drives the various camera
connected through the bleeder resistor R9 to the
components through a gear train, as shown in figure 2-6.
filament of the OPERATE lamp. This extends the life of
the lamp and minimizes the turn-on current of transistor
2-11. Functioning of Intervalometer Circuits
Q2.
a. The Intervalometer circuit functions as a pulse
(2) When there is no film to keep the end of
generator when the camera operates in the pulse mode.
film switch 1A11S1 closed, the +22 vdc regulated is
The output level of the electronic mode switch governs
disconnected from the scan control relay K1 and from
the output frequency of the Intervalometer pulse. The
the scan control relay driver 010, and reconnected to the
scan drive is thus caused to cycle once for each
filament of OPERATE lamp DS2. Camera operation
Intervalometer pulse.
then ceases and the OPERATE lamp illuminates
b. The input to the electronic mode switch
steadily.
operational amplifier AR1 is a v/h vert-1 signal volt
2-11
