FUNAI T3A-A8182DB, Service Manual

Page: 18 / 91

1-8-1 E3B40EA
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 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 [PROG.
L5??
] or
[PROG.
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: 0.001~50V/Div.,
F-Range: DC~AC-20MHz
2.Alignment Tape (FL6A)
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 wave-
form 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.Point Mode Input
J308(JK1-V-OUT)
TP504(RF-SW)
GND
VR501
(Switching Point)
(AV CBA)
PLAY
(SP)
-----
Tape
Measurement
Equipment
Spec.
FL6A Oscilloscope
6.5H
±
1H
(416
µ
s
±
64
µ
s)
Connections of Measurement Equipment
Oscilloscope
Main CBA
J308
CH1 CH2
Trig. (+)
GND
TP504
Figure 1
EXT. Syncronize Trigger Point
1.0H
CH1
CH2
Switching Pulse
V-Sy
0.5H
6.5H
±
1H (416
µ
s
±
64
µ
s)