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ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is an 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.
2.70 perform these alignment
/ confirmation proce-
dures, make sure that the tracking control is set in
the center position: Press either channel "W" or "A"
button first, then the " PLAY " button(VCR's Front
Panel only).
Test Equipment Required
1. Oscilloscope: Dual-trace with 10:1 probe, V-Range:
0.001~50V/Div., F-Range: DC~AC-20MHz
2. Alignment Tape (MH-1)
Head Switching Position Adjust-
ment
Purpose:
To determine the Head Switching point during play-
back.
Symptom of Misadjustment:
May cause Head Switching noise or vertical jitter in
the picture.
Test Point
TP751(V-OUT)
TP302(RF-SW)
TP501(GND)
Adj. Point
VR501
(Switching Point)
(MAIN CBA)
Measurement
Equipment
Oscilloscope
Spec.
6.5H+1H
(412.7s+60ys)
Connections of Measurement Equipment
Oscilloscope
TP751
TP501
cs
TP302
(e)
CH2
Trig. (+)
Main CBA
Figure 1
Poa EXT. Syncronize Trigger Point
"
41 1 . 0 H
TORIES
ety
Switching Pulse
Reference Notes:
Play back the Alignment tape and adjust VR501 so that
the V-sync front edge of the CH1 video output waveform
is outthe 6.5H(412.7ps) delayed position from the rising
edge of the CH2 head switching pulse waveform.
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