GE 4PE350A3 Instructions Manual page 40

EBI-6351
COLOR CAMERA
Luminance Video Amplifier Board,
PL -7674514
Refer to Figs. 18 through 21.
SIGNAL INPUTS
Using the oscilloscope, check the squash
pulse at the input side of C12. It should be
4.0 volts ± 0.5, 7 microseconds wide, at a
15 -kHz rate.
Check the W video input at TP-1. The
input video should be typically 0.20 volt.
BANDWIDTH
Set R18 fully CW, R25 fully CCW, and R31
to mid -range. Using a video sweep generator,
apply sweep to the input and adjust the level
for 0.7 volt peak -to -peak at the output, TP-2.
The sweep should be flat to 8.0 mHz ± 1.0 db
and down 3.0 db at 10 mHz, If necessary,
readjust C2 for the best bandwidth, using
these two points as reference.
GAIN
Using a Camera signal such as a gray
chart, set the video level control, R2, to
give an amplitude of 0.15 volt peak -to -peak
at R2-2. The output of the luminance am-
plifier should be 0.7 volt ± 0.1 at TP-2.
APERTURE CLIPPER
Set R12 to the center of its range. Using
an ordinary Camera signal, adjust R2 to
produce a 0.7 volt peak -to -peak output at
TP-2. Set R25 and R31 to mid -range. Using
the oscilloscope, check the signal on the
emitter of Q7. It should be possible to go
from no clipping to full clipping by adjusting
R12. Repeat, checking the signal on the emit-
ter of Q11.
VIDEO LEVEL
With an output of 0.7 volt peak -to -peak,
the d -c voltage at the video level pin, J1-6,
to ground should be 0.7 volt ± 0.1 as read
on a 20,000 ohm -per -volt meter.
26
TEST POINTS
Refer to the Schematic Diagram for the
location of the test points which are used
to facilitate setup and maintenance.
Chrominance Video Amplifier Board,
PL -7674505
Refer to Figs. 22 through 25.
SIGNAL INPUTS
Using the oscilloscope, check the squash
pulses at the input side of C104, C204, and
C304. The squash pulse should be 4.0 volts
± 0.5 and 7 microseconds wide at a 15 -kHz
rate.
Check the red, green, and blue video inputs
at TP-101, TP-201, and TP-301, respectively.
The input video signal should be 0.30 volt
± 0.1.
GAIN CHECK
Adjust the video level control, R102, R202,
or R302, to give an amplitude of 0.15 volt
peak -to -peak at R102-2, R202-2, or R302-2.
The output of the chrominance video ampli-
fier should be 0.7 ± 0.1 volt peak -to -peak at
J1 -A, J1 -F, or J1 -M.
BANDWIDTH
Using a video sweep generator, check the
bandwidth of the amplifier at the 5- and
10-mHz points. It should be 0.5 db at 5 mHz
and 3.0 db ± 1.0 at 10 mHz. If necessary,
adjust C102, C202, and C302 for the best
bandwidth, using these two points as ref-
erence.
VIDEO LEVEL
With an output of 0.7 volt peak -to -peak, the
d -c voltage at the video level pins, J1-1,
J1-4, and J1-13, should be 0.7 volt f 0.1 as
read on a 20,000 ohm -per -volt meter.
TEST POINTS
Refer to the Schematic Diagram for the
location of the test points which are used to
facilitate setup and maintenance.