Sony PS-X75 - Page 8

PS-X75 |
1-4-3.
Tonearm
Swivelling
Circuit
(see
Fig.
3):
Turning the power switch on returns the tonearm
to the arm rest.
[ > : BACK]
When S507 ( > : BACK) is turned on, the voltages
at terminals (17) and (18) of IC102 become high “1”.
This turns the voltages at terminals (6) and (7) of
IC110 respectively to positive and negative. <A
negative voltage then appears at terminal (1) of
IC110.
FORWARD
1-4-4, Tonearm Lifting Circuit (see Fig. 4):
When the arm lifter is lowered in the zero balance
are, Q108 turns off because the voltage at terminal
(20) of IC102 is high “1”. As a result, varying
RV502 (STYLUS FORCE:ANTI SKATING) causes
no change in the stylus force.
However, since the voltage at terminal (23) of
IC102 becomes low “0”, a positive voltage appears
at terminal (1) of I1C109, turning Q121 on. This
causes current to pass through L501 (vertical drive
coil) in direction A and lifts the tonearm. This
function helps apply a constant stylus force when
the tonearm is moved forward or backward, thereby
preventing the arm from deflecting.
Also, since the voltage at terminal (26) of 1C102
becomes low “0”, Q133 turns off. This lowers the
gate voltage of Q132, resulting in no MFB current
which would otherwise generate in L502, with the
movement of the tonearm. When the arm lifter is
Fig. 3
As
a
result,
Q125
turns
on
to
pass
current
through
L503
(horizontal
drive
coil)
in
direction
A,
returning
home
the
tonearm.
[<d: FORWARD]
When S506 (<: FORWARD) is turned on, the
voltages at terminals (15) and (16) of IC102 become
high “1”, This turns the voltage at terminal (1) of
IC110 to positive, and, consequently, switches Q124
on.
Now that Q124 is on, current flows through L503
in direction B, moving forward the tonearm.
lowered outside the zero balance area, Q108 turns
on because the voltage at terminal (20) of IC102
becomes low “0”. Asa result, varying RV502 causes
voltage ranging from 0 to 5 volts to be applied to
terminal (6) of IC109. A negative voltage then
appears at terminal (1), turning Q122 on.
Now that Q122 is on, L501 has current pro-
portional to the stylus force in direction B.