TM 5-6675-319-14
(4) The slow edge raster controls consist of voltage comparators Q3 and Q4
on card 3CC1 and front panel RASTER edge control potentiometers R137 and R138. The
circuits allow the top and bottom rasters to be independently controlled. The input
signal is the staircase voltage across R37.
(5) The slow axis toggle is a modified Schmitt trigger. The output is
positive during exposure and negative when the exposure mode is complete. The
positive and negative outputs are applied to the run/stop flip-flop and the CRT
b l a n k i n g c i r c u i t.
(6) The run/stop flip-flop consists of Q6 thru Q8 on card 3C2. The flip-
f l o p i s t r i g g e r e d “ o n ” by platen handle microswitches S107 and S201 during multiple-
p r i n t o p e r a t i o n .
It is triggered “off” by a negative pulse from the slow axis
t o g g l e.
Unless affected by the time delay circuits, exposure begins when the hood
is lowered and locked, and ends when the slow axis sweep reaches the bottom raster
e d g e l i m i t .
The run/stop flip-flop output is applied to the reset network and the
APL Control circuits.
(7) The reset network consists of Q1 and Q2 on no. 2 card 3D2. When the
r u n / s t o p f l i p - f l o p i s t r i g g e r e d “ o f f ”, the output of the reset network disables the
input to operational amplifier A1.
W h e n t h e r u n / s t o p f l i p - f l o p i s t r i g g e r e d f o r t he
next exposure, the reset network starts the slow axis integrator again.
(8) The CRT blanking circuit consists of Q1 and Q2 on card VDSF2. Inputs’
are from the slow axis toggle and sweep failure detection circuits.
I f e i t h er
circuit is enabled, the CRT Blanking circuit is activated and the CRT is blanked.
(9) Sweep failure detector A1A, A1B, A2A, and A2B monitors the fast axis
sweep.
If the sweep rate drops too low, the failure detector activates and supplies
a signal to the CRT blanking circuit .
Test switch S104 and reset switch S105 are
used to check the sweep failure detection circuit for proper operation.
( 1 0 ) T i m e d e l a y c i r c u i t:
A time delay on exposure delay card EDC1 permits
exposure to start after a 3 to 6 sec time delay. The time delay is useful when
printing glass plates, as it allows for a more positive contact with the printing
surface before exposure starts .
(11) With EXPOSURE DELAY/NORMAL switch S102A set to NORMAL and the hood up,
relay K1 is energized by +12.5 V applied to Q2 thru S107 (platen handle micro-
s w i t c h ) .
With K1 energized, +12.5 V is removed from the run/stop flip-flop and
applied to the reset network through MODE switch S103. The +12.5 V ensures that the
slow axis deflection circuits are disabled and the CRT is blanked while the hood is
up.
(12) When the hood is down and EXPOSURE DELAY/NORMAL switch S102A is in the
NORMAL position, S107 removes +12.5 V from Q2.
Relay K1 de-energizes, the reset
network is deactivated, the slow axis deflection circuits are enabled and the CRT is
unblanked.
The +12.5 V is applied to the run/stop flip-flop as a start pulse, thus
beginning the exposure cycle.
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