TM 5-5675-319-14
When the charge on C3 is high enough to forward bias SCR2. SCR2 conducts and NE1
indicates charging circuit is functioning. SCR2 will conduct until the charge on C3
causes it to reverse bias.
The output pulse is coupled through C4 to CR4. When the
ACTUATE pushbutton is depressed, SCR1 and CR4 conduct. The shutter solenoid voltage
increases to approximately 192V for 3 to 5 ms to open the shutter. The output then
decreases to approximately 24V to hold the shutter open for the length of time the
ACTUATE pushbutton is depressed.
When shutter solenoid is energized, the SHUTTER
OPEN IND is on, indicating shutter is open.
Toggle S3 is a three-position switch.
In bulb (B), the shutter is open as long as the spring load switch is in B. In time
( T ) , t h e s h u t t e r i s o p e n i n d e f i n i t e l y .
I n t h e c e n t e r p o s i t i o n , t h e s h u t t e r is
c l o s e d .
d . E l e c t r i c a l s y s t e m.
(1) When primary power is applied and circuit breaker CB1 is closed, power
is applied to the blower motor power switch, high voltage transformer, mag con-
t r o l l e r a s s e m b l y , t i l t c o n t r o l l e r a s s e m b l y , r e c e p t a c l e o n t h e r i g h t c o l u m n f o r t he
electronic shutter and the receptacle on the base assembly for the hand held magni-
f i e r .
The high voltage transformer provides 12 kV ac at 112 mA to the light grid
assembly.
The light grid assembly consists of fluorescent lamps which provide the
l i g h t s o u r c e f o r t h e r e c t i f i e r .
The blower power switch controls the operation of
the blower.
The blower provides filtered air to the fluorescent lamps to prevent
overheating of the film stage.
The electrical system is protected from electrical
overloads by a circuit breaker with an 8.2 ampere thermal overload heater. Radio
frequency interference is reduced by grounding straps located in the base and lamp-
house assemblies.
7-24
