Sony PS-242 - Electrical Adjustments

Tonearm Height Adjustment
A)
1. Bring the tonearm toward the inner of the
record and: put the ‘stylus:in the last. groove
of the record.
2. Slowly turn the turntable by hand to lift the
tonearm.
3. Make sure that the clearance between the stylus
tip and the record is approx. 7mm.
4. - If necessary, adjust the height of the tonearm
by turning the tonearm lifter screw.
5.
After
the
adjustment,
make
sure
that
the
tone-
arm
smoothly
returns
to
the
tonearm
rest.
B)
1. Loosen the screw (A) counterclockwise.
2. Set the arm lift-up button to up position and
adjust the screw so. that the clearance
between the stylus tip and the record surface is
7mm. |
3, Turn again the screw (A) clockwise until the
screw (A) touches the boss.
4. Push the arm lift-up button and check the arm
operation. If the tonearm does not drop
smoothly, adjust by turning again the screw (A).
5. When the stylus drops out of the turntable,
confirm that the stylus tip is more than
1
mm
below
the
surface
of
the
turntable
mat.
6.
After
the
adjustments,
apply
a
drop
of
locking
compound
to
the
screws
(A)
and
Approx. 7mm
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Fig. 4-7 Turntable
Automatic Return Position Adjustment
Reject:the tonearm: by REJECT lever.
Bring the tonearm to the automatic-return test
groove (inside portion) of the test record
(YFSB-6), and adjust the screw for returning
the tonearm. at count 1S. ~.17.
Turning direction Automatic return —
clockwise late
counterclockwise early
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: more than 71mm
tonearm lifter screw
adjustment screw
4-2. ELECTRICAL ADJUSTMENTS
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| Motor Amp Offset Adjustment and Hall Device Gain Adjustment
I,
2
escenario
Short the terminal pins as shown.
Connect three diodes (1OE2) as shown.
Connect VITVM Q) or oscilloscope to H1] and
adjust RV6 for 0 V dc VIVM reading or so that
the waveform on oscilloscope becomes as
shown.
Connect VIVM G) to H1 and adjust RV4 for
1.27 V ac reading on VIVM.
Short the
terminal pins.
Turntable Speed Adjustment
If correct speed cannot be obtained by adjusting
the PITCH control knob, adjust RV1 or RV2.
L.
Set the PILCH control knob to the mechanical-
mid position. |
Set the SPEED selector knob to “45. or “337
position and adjust RV1 or RV2 so that the
stroboscope pattern appears stationary.
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Connect VTVM (2) or oscilloscope to H2 and
adjust RV7 for 0 V dc VIVM reading or so that
the waveform on oscilloscope becomes as
shown.
Connect VTVM (1) to H2 and adjust RVS for
1.27 V ac reading on VIVM.
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Note: Set the sweep time longer as for easy
waveform checking. :
Fig. 4-9
RVI RV2
(45 rpm) (33 4pm)
TPITCH CONTROL BOARD]
Fig. 4-10