Panasonic PV-M2738 Operating, Руководство по обслуживанию

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2-24
Tape Running
Condition Audio Control
Head in Tilted
Condition Direction to
turn for
Correction
2. AUDIO CONTROL HEAD TILT ADJUSTMENT
Purpose:
To confirm that the tape runs smoothly. In particular, confirm
that the tape properly picks up the Audio Signal at the upper
part of the head and the Control Signal at the lower part of
the head.
Symptom of Misadjustment:
If the tilt of the Audio Control Head is poorly adjusted, the
tape will eventually be damaged. An intermittent Blue screen
may be seen in Playback.
1. Play back a T120 cassette tape and check that the tape
travels smoothly between the upper and lower guides of the
P4 post.
2. If necessary, adjust Black Screw (B) clockwise until the
tape begins to curl at the lower edge of the P4 post. Then
adjust the screw counterclockwise until the curling is
eliminated.
Fig. M7
3. AUDIO CONTROL HEAD HEIGHT
ADJUSTMENT
The height of the Audio Control Head replacement part is
preset at the factory.
Purpose:
To be sure the tape runs properly along the Control Head.
Symptom of Misadjustment:
If the control signal is not properly picked up, Servo Operation
cannot be achieved. A Blue screen will be seen in Playback.
This confirmation is required when the Audio Control Head is
replaced.
1. Play back a T120 cassette tape and check that the lower
edge of the tape runs approximately 0.25 mm above the
lower edge of the Audio Control Head.
2. If necessary, adjust Black Screws (A) and (B) clockwise to
lower the tape or counterclockwise to raise.
4. AUDIO CONTROL HEAD AZIMUTH
ADJUSTMENT
Purpose:
To adjust the position and height of the Audio Control Head
so that it meets the tape tracks properly.
Symptom of Misadjustment:
If the position of the Audio Control Head is not properly
adjusted, the Audio S/N Ratio is poor.
1. Connect the oscilloscope to the TP4002 on the Main C.B.A.
2. Play back the 6kHz Monaural Audio portion of the alignment
tape.
3. Adjust Black Screw (C) on the Audio Control Head base so
that the output level is at maximum.
Fig. M9
4. Confirm the height of the Audio Control Head is proper. If
not, readjust Black Screws (A) and (B).
Black Screw (B)
Black Screw (C)
Black Screw (A)
Control Head
Lower Edge
of Control Head
0.25mm
Lower Edge
of Tape
Fig. M8
Maximum
6KHz-Audio