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5-3 Solenoid drive circuit
39K
to FWO.REV GATE
Q107
Si
R229
When activated, tonearm is
lowered down.
At fi
is activated at 12 V
afterwards at 9 V.
Backlash protection
at coil
OFF
1¢201
R223
560
se AM
DO Solenoid
(tor PU DOWN)
oer
a
10201
2fE>o!
10K
up
at
0202
0.022u
sv
R201
10K
PLAY 7.5V ~>AWAE—j—4
201
0.02244
Time constant cir-|%
pos
cuit of R221, C-
207 and R217 for
monostable multi-|KEEP@B
vibrator.
When tonearm is lifted up, 0203
is OFF and Q204 ON. When tone-
arm is lowered down, 0203 is ON
and 0204 OFF. The latter state of
the monostable multivibrator is
inverted in about 2.5 sec.
Fig.8
Solenoid Drive Circuit
This circuit is as shown in Fig. 8.
This circuit is controlled
by the arm UP/DOWN
signal to activate the solenoid by which the tone-
arm is lifted up or lowered down. 0203 and 0204
from a monostable multivibrator. Normally (when
the tonearm
is lifted up), Q203
turns OFF and
Q204 ON. Thus, pin 12 of 1C201 becomes ''H'' to
turn Q208
OFF. When the tonearm
is lifted up,
since signal DOWN OUT is "L", pin 13 of 1C201 is
"H"" (the transistor of pin 13 is OFF). Thus, the
solenoid is not activated and the tonearm is at the
UP position.
Next, when
the tonearm
is lowered down, since
signal DOWN OUT becomes "'H", pin 13 of 1C201
is L''. Thus, when Q203 is turned ON and Q204
OFF at the leading edge of signal DOWN
OUT
through
R202
and C202, since the collector of
Q204
is "H'', pin
12 of 1C201
becomes
"L".
+12
V
thereby
serves
to activate
the solenoid
through the route of Q208~>D206-solenoid->1C-
201 pin 13. This activation continues for about 2.5
sec by the time constant circuit of C207, R221 and
R217.
Subsequently,
since the monostable multi-
vibrator of Q203 and Q204 returns to the stable
state
in which
Q203
is OFF and Q204 ON, the
collector of Q204 is 'L" and pin 12 of 1C201
is
"HH", Thus, Q208 turns OFF
and the solenoid
is
held ON by KEEP @) B voltage.
Finally, when the tonearm is released from its rest
by pressing the START switch, the trigger of R201
and C201
functions to actuate the monostable
multivibrator of Q203 and 0204 by PLAY 7.5 V
with
the
REST
switch
at PLAY.
Thereby,
this
trigger acts to temporarily stop the action of the
tonearm
(at the outermost position of the 30 cm
LP record).
Since the distance between the rest and "30 cm"
lead-in positions is short, when the START switch
is pressed for an excessively long time, the mode
changes from auto to manual (play (B)) when the
tonearm
passes through the lead-in position. To
avoid this problem, the above temporary stoppage
is performed, thus assuring the lead-in operation of
the tonearm.
During the period
of the stoppage, since signal
DOWN
OUT
resultant from detecting the lead-in
position
is not
emitted,
the
solenoid
is not
activated. Accordingly, the tonearm is not lowered
down.
-W-
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