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EBI-3641
CHANNEL AMPLIFIER
CORRECTIVE
1.
High -Frequency Response Alignment
The
following procedures should be followed for high -frequency
response alignment.
See Fig.
8
for the test equipment
setup.
1.
Remove
the
VIDEO INPUT coax lead from
Jl.
Do
not remove any
of
the
remaining connections.
2.
Terminate the four 1.0 volt VIDEO OUTputs,
J2
through
J5,
with
75 ohms.
3.
Set the Channel
Amplifier
and control panel controls to the
following positions:
a.
Control panel CONTRAST control
to OFF.
b.
Channel Amplifier GAMMA ON-OFF switch
S3 to OFF.
c.
Channel Amplifier CABLE
COMP
switch
S2 to zero.
d.
Channel Amplifier APER CORR switch
S1
to
1.
e.
Control panel VIDEO REVERSAL switch
to
POSITIVE.
f.
Channel Amplifier SETUP control R198
to OFF.
g.
Control panel BLANKING control
to
midrange.
h.
Remove tube V12 in
the Channel Amplifier.
4.
Connect the detector probe and oscilloscope
to one of the
non
-
composite video outputs,
J2 or J3.
5.
Connect the sweep generator output
to V8-1, and adjust C50
and C53 for
a
flat response
to 10
megacycles
±
1
db.
Use the detector and
sweep probe
as
shown in
Fig.
8.
6.
When sweeping the Channel Amplifier, keep the oscilloscope gain
high and the sweep generator output
low.
This prevents overloading.
7.
Connect
the sweep generator output to
V5-2 and adjust the
BLANKING control for maximum over-all gain without affecting the
sweep
envelope.
Adjust L6
and C38
for
a
flat response
to 10
megacycles
±
1 db.
8.
Connect the sweep generator output
to
V3A-2 and adjust L5 and
C31 for
a
flat response
to 10
megacycles
±
1 db.
9.
Connect the sweep generator output
to Jl and adjust the
CONTRAST control for
maximum gain
(cw).
Adjust
the
BLANKING ADJ
POS
control, R28, for
minimum modulation
of sweep envelope.
Set the VIDEO
REVERSAL switch
to
NEGative and adjust the BLANKING ADJ NEG
control, R29,
for
minimum modulation
of the sweep envelope.
Return
the
VIDEO REVERSAL
switch
to POSitive.
10.
Connect the sweep generator output
to
V2-2 and adjust L2 and
C11 for
a
flat response
to 10
megacycles
±
1 db.
11.
Connect the sweep generator output
to Jl and
adjust Ll for
a
flat response
to 10
megacycles
±
1 db.
12
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