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Chapter 3. Mechanism
3-1 Tonearm mechanism
The tonearm
is lifted up or lowered down
by
operating the solenoid plunger by the arm UP/
DOWN
signal of the control
circuit. When the
solenoid
is activated, the rod is rotated by the
3-2 Tonearm movement control
Secondly, the rotating direction of the carry motor
is controlled
by the FWD/REV
signal. Thus, the
tonearm
is forwarded
or reversed along the rod
together with the carrier on which the tonearm is
mounted.
In this case, only when
the arm
UP/
DOWN
sensor detects that the tonearm is being
lifted up, the tonearm is forwarded or reversed by
an operation button.
Thirdly, the position of the tonearm is detected by
the brush' mounted
at the rear part of the carrier
Position sensor
Carry motor
Spring
4
3C
Roaf
angle
Carrier
conversion Elevation
arm
arm
Tracking error sensor
Arm UP/DOWN sensor
Compensation guide
Tonearm
angle conversion
arm in a certain direction, thus
the tonearm is lowered down through the elevation
arm.
Differently,
when
the solenoid
is released
from activation, the tonearm is lifted up.
and the position sensor with the electrodes mount-
ed at the lead-in and lead-out positions. Thus, the
tonearm is led in or out as predetermined.
Lastly, the arm deviation angle is detected by the
tracking error sensor and the control circuit func-
tions to forward the tonearm sequentially little by
little by the carry motor. Thus, the tonearm fol-
lows the groove correctly on play.
Fig. 4 shows
the block diagram of the control
circuit.
Each
circuit
block
performs
as follows:
'Shutter
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