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Step
1 - - - -
--
- ~
-
--
-
----<
Oscilloscope
position
No.
V
H
Test
points
IC9,
pin
(2)
CN51-1
Adjustment
positions
VAS
VR3
VIDEO
/DEMB
OUTPUT
Assembly
terminal
VR201
IC10,
pin (27)
VC202
Check items/
Adjustment
specifications
DC0V
2Vp-p
1Vp-p
3.579545MHz
Adjustment procedure
I
11-2 SRVB Assembly Adjustment
Note: The SRVB assembly adjustment can be made with
-
out removing the shield case.
1 )
TBC offset adjustment
•
Turn on the power switch and adjust VR8 so that there
is DC0V at pin (2) of IC9 (NJM4558S) when not playing
back.
Note: When the DC voltage cannot be checked due to noise,
connect L.P.F. and measure as shown in the diagram.
lOOkn
IC9,
pin (2)
~n--- ~
-
•
Oscilloscope
::
O.OlµF
,,,,.
Fig.
11-3
L.P.
F.
for elim inating noise
2) TBC Video Level Adjustment
Note: The ''
1)
Demodulated video level adjustment'' for
the DEMB assembly must be completed first.
•
Search
frame
#
19,801.
•
Adjust VR3 so that the amplitude of the CN 51
-1
video
signal (from the sync chip to the wh ite peak) is 2Vp-p.
•
Check whether the video signal at the VIDEO OUTPUT
terminal on the
rear
panel
is 1
Vp-p. (A 7 5-ohm termina-
tor is used when a video monitor
is
connected.) Use
DEMB Assembly VR201 to make the adjustment.
3) Starting Oscillation Frequency
Adjustment
•
Connect a frequency counter
to
pin (27) of IC10
(PM2001) and adjust to 3.579545MHz
±
5Hz using
VR202.
54
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