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4.
Thread
the tape and set up the record
mode.
5.
Adjust
R731
so that
the PG
pulse
appears
midway
between
the
positive
and
negative
peaks.
See Fig. 4-1.
6.
Stop
the
VTR.
Pull
the
REC
Lever
and
measure
the
time
required
to stop
the
PG
pulse
on
the
rectangular
pulse.
If it takes
more
than 6 seconds, adjust R732.
4-3-3.
50 PG Coil Position Adjustment
Test Point:
TP-708 (CH-1), TP-301 (CH-2)
Adjust
for:
50 PG pulse at the center of
channel overlap.
Adjustment:
50 PG Coil
Signal source:
None
Equipment
Required:
1.
Video
Alignment
Tape
or
Prerecorded
Tape
2.
Oscilloscope
Procedure:
1.
Thread
a SONY
video alignment tape or any
prerecorded
tape
that
is
recorded
by
a
correctly-aligned VTR.
2.
Connect the scope CH-1
probe to TP-708 and
the CH-2
probe to TP-301.
TP-708 is on the
Servo board and TP-301 is on the Demodulator
board.
50PG coil
25PG coil
Fig. 4-2.
42
Fig. 4-3.
3.
Set the scope horizontal time base to 5 ms/cm.
Sync on CH-1 only.
4.
Set up the playback
mode.
5.
Adjust scope controls to observe
both signals.
Then
set the
scope
MODE
SWITCH
to the
CHOP
position.
Pull out
the SX
magnifier
and adjust the HORIZONTAL
POSITION
to
observe the vertical blanking interval.
6.
Bend
the tip of the 50 PG coil with pliers and
adjust
the coil position
so that
maximum
rf
output
is obtained
in
the
overlap
period.
See Fig. 42 and Fig. 4-3.
4-3-4.
30PG
Coil Position Adjustment
Test Point:
TP-304 (CH-1), TP-708 (CH-2)
Adjust for:
50 PG leads VD
by
8H+1H
Adjustment:
25 PG coil
Signal source:
TV telecast signal
Equipment
Required:
1.
Oscilloscope
2.
Monitor TV
Procedure:
1.
Connect
scope CH-1
probe to TP-304
on the
"D1" board and CH-2 probe to TP-708 on "'S1"
board.
Set scope time base to
5ms/em.
Sync
the scope externally from TP-703.
Connect
monitor.
Set TV-CAMERA
Select switch to TV.
i
Set up record
mode.
5.
Set the scope
MODE
SELECT
switch to the
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