Toshiba VTW21FQR, Service Manual

Page: 55 / 116

D2-3
MECHANICAL ADJUSTMENTS
2-3: 2-2:
When the Tape Running Mechanism does not work well,
adjust the following items.
CONFIRMATION AND ADJUSTMENT OF AUDIO/
CONTROL HEAD
1.
2.
3.
4.
When the height is not correct, turn the screw
3
to
adjust the height. Then, adjust the 1~3 again.
Playback the VHS Alignment Tape.
Confirm that the reflected picture of stamp mark is
appeared on the tape prior to P4 Cap as shown in Fig. 2-
2-A.
a)
b)
Turn the screw
2
to set the audio level to maximum.
Confirm that the bottom of the Audio/ Control Head and
the bottom of the tape is shown in Fig. 2-2-C.
c)
When the reflected picture is distorted, turn the screw
1
clockwise until the distortion is disappeared.
When the reflected picture is not distorted, turn the
screw
1
counterclockwise until little distortion is
appeared, then adjust the a).
P4 Cap
Fig. 2-2-A
Audio/Control Head
1
3
2
Fig. 2-2-B
Audio/Control Head
Fig. 2-2-C
TAPE RUNNING ADJUSTMENT
(X VALUE ADJUSTMENT)
Confirm and adjust the height of the Reel Disk.
(Refer to item 1-1)
Confirm and adjust the position of the Tension Post.
(Refer to item 1-2)
Adjust the Guide Roller. (Refer to item 2-1)
Confirm and adjust the Audio/Control Head.
(Refer to item 2-2)
Connect CH-1 of the oscilloscope to TP4501, CH-2 to
TP4502 and CH-3 to Audio Out of 21 Pin Jack.
Playback the VHS Alignment Tape.
Press and hold the Tracking-Auto button on the remote
control more than 2 seconds to set tracking to center.
Set the X Value adjustment driver (JG153) to the
4
of
Fig. 2-2-B. Adjust X value so that the envelope waveform
output becomes maximum. Check if the relation between
Audio and Envelope waveform becomes (1) or (2) of Fig.
2-3.
1.
2.
3.
4.
5.
6.
7.
8.
4
Audio/Control Head
Reflected picture of
Stamp Mark
Stamp Mark
Tape
0.25
±
0.05mm
Envelope
CH-3
Audio
(1)
(2)
Fig. 2-3