Adjustment - JVC DR-MV2SEU Service Manual

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)
SECTION 4

ADJUSTMENT

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.
Test point
J236(JK1-V-OUT)
TP504(RF-SW)
GND
Tape
MHPE
Conne ctions of M easurement Equipment
Main CBA
CH1
CH2
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 (416µs±64µs) delayed position from the rising edge
of the CH2 head switching pulse waveform.
Adj.P oint Mode
VR501
PLAY
(Switching Point)
(MAIN CBA)
Measu remen t
Equipme nt
Oscilloscope
J236
GND
TP504
Figur e 1
EXT. Syncronize Trigger Point
0.5H
1.0H
6.5H+/-1H (416µs+/-64µs)
Switching Pulse
Input
-----
(SP)
Spec.
6.5H±1H
(416µs±64µs)
Oscilloscope
CH1 CH2
Trig. (+)
V-Sync
(No.YD087)1-27