Toshiba D-VR610KU, Руководство по обслуживанию

Страница: 19 / 87

1-7-1 E9KGAEA
ELECTRICAL ADJUSTMENT INSTRUCTIONS
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 com-
pleted. Also, do not attempt these adjustments
unless the proper equipment is available.
2.To perform these alignment / confirmation proce-
dures, make sure that the tracking control is set in
the center position: Press either [TRACKING ]
or [TRACKING ] button on the front panel first,
then the [
O
] (VCR) button on the front panel.
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 (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.
Reference Notes:
Playback the Alignment tape and adjust VR1501 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 switch-
ing pulse waveform.
NOTE: BOARD MEANS PRINTED CIRCUIT BOARD.
Test point Adj.Point Mode Input
TP751(V-OUT)
TP302(RF-SW)
GND
VR1501
(Switching Point)
(BOARD MAIN)
PLAY
(SP)
-----
Tape
Measurement
Equipment
Spec.
FL8A Oscilloscope
6.5H
±
1H
(416
μ
s
±
64
μ
s)
Connections of Measurement Equipment
Oscilloscope
BOARD
Main
TP751
CH1 CH2
Trig. (+)
GND
TP302
Figure 1
EXT. Syncronize Trigger Point
CH1
CH2
1.0H
0.5H
V-Sync
Switching Pulse
6.5H
±
1H (416
μ
s
±
64
μ
s)