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ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is abbreviation for
"Circuit Board Assembly."
NOTE:
1. Electrical adjustments are required after replacing
circuit components and certain mechanical parts.
It is important to do these adjustments only after
all repairs and replacements have been
completed. Also, do not attempt these adjustments
unless the proper equipment is available.
2. To perform these alignment / confirmation
procedures, make sure that the tracking control is
set in the center position: Press either [CHANNEL
L] or [CHANNEL K] button on the front panel first,
then the [VCR PLAY] button on the front panel.
Test Equipment Required
1. Oscilloscope: Dual-trace with 10:1 probe,
V-Range: 0.001~50 V/Div.,
F-Range: DC~AC-20 MHz
2. Alignment Tape (FL8A)
Head Switching Position
Adjustment
Purpose: To determine the Head Switching position
during playback.
Symptom of Misadjustment: May cause Head
Switching noise or vertical jitter in the picture.
Test point
JP4017(V-OUT)
TP4302(RF-SW)
GND
Measurement
Tape
FL8A
Connections of Measurement Equipment
JP4017
AV CBA
GND
TP4302
EXT. Syncronize Trigger Point
CH1
1.0H
6.5H±1H (412.7µs±63.5µs)
CH2
Switching Pulse
Note: JP4017 (V-OUT), TP4302 (RF-SW),
VR4501 (Switching Point) --- AV CBA
Reference Notes:
Playback the Alignment tape and adjust VR4501 so
that the V-sync front edge of the CH1 video output
waveform is at the 6.5H ± 1H (412.7 µs ± 63.5 µs)
delayed position from the rising edge of the CH2 head
switching pulse waveform.
1-8-1
Adj. Point
Mode
VR4501
PLAY
(Switching
(SP)
Point)
Spec.
Equipment
6.5H ± 1H
Oscilloscope
(412.7µs±63.5µs)
Oscilloscope
CH1
Trig. (+)
Figure 1
0.5H
E4340EA
Input
-----
CH2
V-Sync
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