JVC DR-MV2SEU, Руководство по обслуживанию

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(No.YD087)1-27
SECTION 4
ADJUSTMENT
4.1 ELECTRICAL ADJUSTMENT INSTRUCTIONS
General Note: "CBA" is an abbreviation for "Circuit Board As-
sembly."
NOTE:
(1) Electrical adjustments are required after replacing circuit
components and certain mechanical parts.
It is important to do these adjustments only after all re-
pairs and replacements have been completed. Also, do
not attempt these adjustments unless the proper equip-
ment is available.
(2) To perform these alignment / confirmation procedures,
make sure that the tracking control is set inthe center po-
sition: Press either ”PR -” or “PR +” button on the front
panel first, then the VCR “
“button on the front panel.
4.1.1 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 (MHPE)
4.1.2 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.
Reference Notes:
Playback the Alignment tape and adjust VR501 so that the V-
sync front edge of the CH1 video output waveform is at the
6.5H±1H (416
µ
s±64
µ
s) delayed position from the rising edge
of the CH2 head switching pulse waveform.
Test point Adj.P oint Mode Input
J236(JK1-V-OUT)
TP504(RF-SW)
GND
VR501
(Switching Point)
(MAIN CBA)
PLAY
(SP)
-----
Tape
Measu remen t
Equipme nt
Spec.
MHPE Oscilloscope
6.5H±1H
(416µs±64µs)
Conne ctions of M easurement Equipment
Figur e 1
Oscilloscope
Main CBA
J236
CH1 CH2
Trig. (+)
GND
TP504
EXT. Syncronize Trigger Point
1.0H
CH1
CH2
Switching Pulse
6.5H+/-1H (416µs+/-64µs)
V-Sync
0.5H