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5.1.3 Elevation and Tonearm Circuits
The tonearm drive motor and EV solenoid are controlled
by commands from the control IC (01 ), which also con
trols the horizontal and vertical movement of the tonearm.
In addition to this, the IC controls tonearm tracking with
the tracking sensor and tracking error signals.
• EV solenoid drive
The EV solenoid drive uses a large current at first to
draw the plunger inside, and thereafter uses a lower current
for holding the plunger in.
The signal to draw the plunger inside comes from the
control IC (01), passes through the 02 transistor array, and
enters 03 pin 8. This signal turns on the 03 Darlington
transistor, and approximately 170mA of current runs into
the collector, turning on the EV solenoid which draws the
plunger inside. Because of this, the tonearm will drop
slightly. This "draw" signal from the control IC lasts about
1 second. Next, the hold signal, which was output at the
same time as the draw signal, passes through the 02 tran
sistor array, enters 03 pin 7 and turns on the Darlington
transistor. When the draw signal ends, a current of ap
proximately 70mA drawn from pin 10 holds the plunger
inside, which keeps the tonearm elevation down until the
hold signal ends.
+ 12V
• Tonearm drive
The tonearm drive is controlled by input to 03 pin 4,
pin 5, and pin 15. Their truth values are shown in Fig. 5-4
• Lead-in (locate-in)
03 receives locate-in signals from the control IC (01 ),
and with an output of approximately OV from 03 pin 14
(01) and approximately 11 V from pin 11 (02), the tone
arm motor begins turning in the lead-in direction.
• Lead-out (locate-out)
03 receives locate-out signals from the control IC (01).
and with an output of approximately 11 V from pin 14 and
approximately OV from pin 11, the tonearm motor begins
turning in the lead-out direction.
• Stop
03 receives stop signals from the control IC (01 ), and
with an output of approximately OV from both pin 14 and
pin 11, stops the tonearm motor.
• Tracking
03 receives tracking signals from the control IC (01 ),
and between pin 14 and pin 11, outputs an amplified
tracking error signal (amplified by an internal OP am
plifier) and begins turning the tonearm drive motor in
such a way as to correct the error.
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Fig. 5-4 Elevation and Tonearm Drive Circuit and 1/0 Truth Value Chart.