Sharp VC-90ET

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ADJUSTMENT
OF
SERVO
CIRCUIT
Adjustment
of
PAL
System
playback
switching
point
Me rUent Oscilloscope
Test point CH-1; TP2
CH-2; Video output
Control R751 (phase genrator MM
control)
2. Press both tracking control button at the same
time to set the tracking in center.
terminal.(CH-1 trigger slope
Specification 6.5+0.5H
3. Adjust R751 (phase generator MM control) so that
Playback
(tracking at center)
switch at (+), Internal
1. Insert the PAL system alignment tape (VROCPSV)
the waveform on the oscilloscope screen be as
Alignment tape (VROCPSV)
trigger at CH-1 side)
and put the unit in the playback mode.
shown in Figure 2-2.
CH-2
(Video output)
CH-1
FE
6.5H
CH-1; 2V/div 50 psec/div
CH-2; 1V/div 50 psec/div
Figure 2-2.
Adjustment of NTSC System playback switching
point
Oscilloscope
Playback
(tracking at center)
Alignment tape (VROATSV)
CH-1; TP2
CH-2 ; Video output
terminal. (CH-1 trigger slope
switch at (+), Internal
trigger at CH-1 side)
R753 (phase genrator MM
control)
6.5 +0.5H
1. Insert the NTSC system alignment tape (VROATSV)
and put the unit in the playback mode.
2. Press both tracking control button at the same
time to set the tracking in center.
3. Adjust R753 (phase generator MM control) so that
the waveform on the oscilloscope screen be as
shown in Figure 2-3.
Measuring
instrument
Tape used
Test point
Control
Specification
33
— -VC-90ET
CH-2
(Video output)
CH-1 | < 6.5H
CH-1; 2V/div 50 psec/div
CH-2; 1V/div 50 psec/div
Figure 2-3.
Adjustment of PAL System SP Slow tracking
Measuring
instrument
Monitor
TV
-
Recording and playback on self-
recording tape.
Commercial broadcast or video
signal. ;
(external input selector switch)
Input signal
Monitor screen
Tracking contro! button ( +), (-)
No noise bar on the monitor TV
screen.
Test point
Adjusting point
Specification
1. Play back the self-recorded tape in the PAL System
SP slow tracking mode. —
2. Make the cathode of the timer D5003 and cathode
of D5006 short-circuited.
3. Be sure that all the fluorescent display tubes light
up.
4. Remove the short-circuit and make sure that
“CASS” appears on all the above display tubes.
5. Adjust the tracking contro! using the TRACKING
button on the main unit or the remote controller
so that there is no noise on the screen.
Adjustment of NTSC System SP slow tracking
Recording and playback on self-
recording tape.
Commercial broadcast or video
signal.
(external input selector switch)
Tracking control button (+), (-)
No noise bar on the monitor TV
screen
1. Play back the self-recorded tape in the NTSC
system SP slow tracking mode.
2. Make the cathode of the timer D5003 and cathode
of D5006 short-circuited.
3. Be sure that all the fluorescent display tubes light
up.
4. Remove the short-circuit and make sure that
“CASS” appears on all the above display tudes.
Measuring
instrument
input signal
Test Point
Adjusting point
Specification
;