Sony PS-X7 - Page 34

aute-return
operation
START/STOP
t
1
(switch:
ON)
switch
(S5)
0
| 1 (inversion)
start/stop (D1 lights up)
flip-flop NN | Ro
(inversion)
: N ae ’ (motor rotates)
motor flip-flop
}
le i
REPEAT | |
switch (S6) 0
repeat flip-flop oo ee 2
—— itch:
play
switch
oer
ae
a
(switch:
ON)
return
switch
|
|
"
-+-—
1
(switch:
ON)
(S4) it | 0
|
+t
1
(during
solenoid
operation)
solenoid
operation
|
i
0
|
|
|
|
h—1
(0410:
ON)
reset
(Q410)
7
0
I | ! 7 (output)
: 0)
auto-return ou tput .
(S5 START) |
(lead-in has been
completed)
Operation during auto-return
(return detection)
Fig. 3-5.
Speed Detection Circuit
S3 (play switch)
when playing
to Q405
(solenoid drive
switching
transistor)
P
suto-return
detection
Shutter
aarg Scasy PL!
Fig. 3-7.
This circuit, a form of speed detection circuit,
is designed to detect sudden changes in i, due to the
changes in the collector voltage (Vrp) of Q418. i, is
given by the following expression:—
i, = “2 - C417
Gradual changes in the position of the detection
shutter (due to changes in position of the tonearm as
it traces the record groove) result in a change of the
amount of light received by the CdS element, thereby
reducing its resistance. Then when the amount of
change in the detection shutter becomes large, i,
approaches i,, and Q417 is consequently turned off.
Therefore, B+ voltage is supplied to the solenoid
drive circuit through R442, thereby activating the
auto-return mechanism.
In the circuit diagram shown above, D415 and
R444 are employed to prevent misoperation when
the tonearm is moved rapidly across by hand during
the lead-in operation. (i, is increased, thereby
reducing the sensitivity.)
SONY-00830 / DRUCK 18
| PS-X6/X7 PS-X6/X7 |
ust Ee
3-4. Operation during Auto-return (See Fig. 3-6) 5.
1. When the power switch (S1) is turned on,
Q419, Q420 and Q421 are all turned on. The
auto-return operation detector lamp PL1 lights 6.
up.
2. The tonearm gradually moves across to, and
then enters the auto-return position detection 7.
range (within 56.5 mm from the center spindle).
3. Once within the detection range, the pitch of 8.
the phonograph record groove changes rapidly
(i.e. at the lead-out groove), the speed detection 9.
circuit (described later) is activated, turning
Q417 off, and Q405 on (route G3 ).
4. Q407 is also consequently turned on, passing 10.
a current through to the solenoid (PM)
(route @).
Activation of the solenoid (PM) operates the
auto-return mechanism, thereby bringing the
tonearm back to rest automatically.
When operating the auto-return mechanism,
the return switch (S4) is turned on mechanical-
ly, and C414 discharges.
Once the tonearm returns to the arm rest, this
return switch is turned off again.
While C414 is recharging, Q410 is turned on
(route @)).
As a result, all flip-flops are reset, the start
indicator (LED) D1 turns off, and the motor
stops rotating.
The circuitry is thus restored to the original
status.
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9206
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SPEEO DETECTING
HEAD
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[START/STOP] TOF 9403,4 404 2SC633A
SARIS TO TRIGGER PULSE GENERATOR
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10k
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1T40
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Q408,409 2SC633A = Q410_ 2SC 6334 Q411,412 2SC633A
START/STOP FLIP-FLOP RESET MOTOR ORIVE FLIP-FLOP
3 cao, cag
Q415,416 2SC633A
REPEAT FLIP-FLOP
R430 C412
10k
0410~ 413 1T40
paogs 0405,406 2SC633A Q407 28CI475
330k SWITCHING SOLENOID ORIVE
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V/S50V__1/50V
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