Advertisement
DOWN OUT
from 1C102 3)
|=DOWN
tap)
+7.5V
R150
}00
To Solenoid Drive
—twhi
7
1 | While the tonearm is lifted
This circuit performs
the arm UP/DOWN,
operation.
up, this is ON, thus turn-
ing OFF Q202 and Q209.
The resistance value
changes
according
nel
to the amount of
light.
Shuttor
0602
Tracking Error Compensator
vR201
The light of the LED is
shielded with the arm de-
viation angle. The voltage
at Q601 decreases.
R230 5.6K
1c2o1
Arm Carry Motor Drive
\
This circuit functions to slide
Test point for adj
the tonearm inwards or out-
Tracking
E r r o r Compensati
Facking Error:
Compensator
wards. IC201A is used exclu-
the arm trac
increas
When the arm deviation angle is detected,
the voltage at Q201 decreases, the voltage at
0202 increases and the voltage at Q209
sively for tracking.
Fig. 9
This circuit of the sensor and compensator is as
shown in Fig. 9.
This circuit provides the linear tracking action dur-
ing play. It detects the arm deviation angle to slide
the tonearm according to the detection.
The horizontal tracking error of the tonearm
is
detected by the tracking error sensor (consisting of
an LED
and a phototransistor)
mounted on the
carrier and the shutter placed at the tonearm. As
shown in Fig.
10. This detection makes use of the
fact that the emitter voltage of Q601
(photo-
transistor) varies when the shutter shields the light
of LED
D602.
The shutter controls the passing
amount
of the light according to the amount of
the tracking error. Thus, the emitter voltage of
Q601 decreases, the voltage at Q201 decreases, the
voltage at Q202
increases, the voltage at Q209
increases and the voltage at Q205 increases. When
pin 9 of IC201 thereby becomes "H", the carry
motor
performs
the
FWD
rotation
to slide the
tonearm (analog control).
When the tonearm is lifted up (signal DOWN OUT
at "L"), D201 is used to prevent the tonearm from
sliding at Q202 OFF and Q209 OFF even when
tracking error occurs. The base voltage of Q202 is
the bias voltage which determines the operating
point of the tracking error compensator
which
includes a differential circuit of Q201 and Q202.
This circuit is subject to temperature compensation
by TH201. VR201
is used for adjusting the tone-
arm tracking sensitivity and its level determines the
deviation
angle at which
the tracking error
is
compensated.
Carry motor
Carriér
conversion Elevation
arm.
arm.
| "Angle
P.C. Board
'
Tonearm
Ba |
'Solenoid | Tracking error sensor
plunger
'Arm UP/DOWN sensor
|
Compensation guide'
¢Ht
FWwO=++REV
Fig. 10
-12—
Shutter
Advertisement
