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4.12
PCB-VIDEO CIRCUIT ADJUSTMENT
4.12.1
Pedestal Level Adjustment
a.
Apply composite video signal of lVp-p to the input
terminal
o~
the Green channel.
b.
Set the R,G,B Contrast controls (VRlOl, VRlll and
TR121) on PCB-VIDEO-SUB.AND THE Gain control
(VR291) at the center of rotation range.
c.
Using a de oscilloscope, adjust Clamp Level
control (VR291) on PCB-VIDEO to
oLtai~
lOOV
+
lV
of the pedestal level at terminal 6 on the CRT
socket.
4.12.2
Frequency Characteristics
a.
Apply composite sweep signal of lVp-p to the input
terminal o: the RED and GREEN channels.
b.
Adjust the Contrast control and the
Gai~
control
to obtain the output of 40Vp-p (at a frequency of
less than 500KHz) at the RED output on PCB-VIDEO
using an oscilloscope.
c.
Connect a 10:1 probe of an oscilloscope through
a coupling capacitor (lpF) to terminal
8
on PCB-
CRT.
d.
Adjust L20l and L202 in order that variations in
the frequency range of
1 -
40 MHz to be ::3 dB.
e.
Adjust the BLUE channel and GREEN channel in the
same way.
GREEN-terminal
6-Coils
L231, L232
BLUE-terminal
11-Coils
L261, L262
4-10
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