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11. ADJUSTMENTS
11.1 TRACKING SENSOR ZERO ADJUSTMENT
1.
Raise the arm elevation, and adjust VR2
so
that the voltage reading between the TP1 and
TP2 (Control ass'y XWM-058)
test points is
+0.5.
Then move arm elevation up and down several
times and return it to the up
position. Check
that the voltage across TP1 — TP2 does not
exceed +2V (Fig. 11-1).
*Repeat the above
steps until the specified
rating is satisfied.
*When
lifting the arm elevation, also check
that
the stylus is 9mm
+2mm
above
the
record surface, and
that the
elevation
tip
rests in the V-shaped groove (Fig. 11-2).
If the voltage across
TP1
and TP2 exceeds
+2V
asa
result of 'play' in the elevation
bearing of tonearm, the tonearm is considered
defective and must be replaced.
11.2 LOCATE SPEED ADJUSTMENT
1.
Remove the platter and the upper cover, and
check that the turntable and the carrier ass'y
are both horizontal.
Also check that a suitable tracking force has
been set.
Keep
the locate-in button
(< ) depressed at
the 1st level, and adjust VR4 so that the stylus
tip moves
at a rate of 50mm
in 7.1+0.7
seconds (Fig. 11-1).
In the same way, keep the locate-out button
(» ) depressed at the 1st level, and adjust VR3
to again obtain
at stylus tip movement
of
50mm in 7.1+0.7 seconds (Fig. 11-1).
11.3
TONEARM
LOWERING
POSITION
AD-
JUSTING
When
the tonearm doesn't lower in the right
position during automatic playback, adjust accord-
ing to the following procedures. (Be careful not to
damage the record disc with the stylus while mak-
ing this adjustment.)
1. Place a 30cm record on the platter.
2. Depress the playback
START/STOP
button
and start automatic playback. Note the direct-
:
ion and amount the lower position is off. (@)
3. Depress the arm elevation switch and raise the
tonearm (arm-elevation lamp Y_ illuminated.).
"
(@)
4. Depress the power switch to turn power off. (@)
5. After
the platter stops turning, remove the
48
rubber plug from the adjustment screw hole.
9.
1.
2.
:
3.
Adjustment
screw
Fig. 11-2 Arm-elevation adjustment
4,
5.
8 Tonearm lowers toward
Adjustment
inside of record.
a hole rubber
Turn adjusting
screw in direction
of arrow (7).
® Tonearm lowers on the
outside of record.
Turn adjusting
screw in direction
of arrow ().
Fig. 11-3 Tonearm lowering position adjusting
49
Using a small flat-bladed screwdriver, turn the
adjustment screw to correct the offset noted in
item 2. above. (@)
e When
the stylus lowers to the outside of
the record, turn the screw clockwise (°- ).
e When the stylus lowers too far to the inside
of the record, turn the screw counterclock-
wise (>).
Turn power on again ( ©) ), depress the play-
back
START/STOP
buttom
and
return
the
tonearm to the arm clamp. (©)
Depress
the playback
START/STOP
buttom
and check the adjustment (@ ). If the lower-
ing position is still off, repeat steps 3. through
8 above.
Replace the rubber plug after adjustment has
been completed.
11.4
MOTOR
OPERATING
POINT
ADJUST-
MENT
Set the speed to 33 1/3 rpm and depress the
START/STOP
button to put the unit into the
operational mode.
Connect a buffer amp to pin 1 of IC PA2007,
and
connect
the
output
to a_
oscilloscope
(Fig. 11-4).
When a waveform like that shown in Fig. 11-5
is obtained,
vary oscilloscope
gain until
a
sawtooth
wave
with
5 div peak-to-peak
is
obtained.
Then, referring to Fig. 11-5, adjust
VRI1 until a to b equals 3 to 2.
(Make sure
noise does not affect adjustment.)
When the 33 1/3 rpm adjustment is completed,
adjust VR2 using the same procedure (item 2
and 3 above) for 45 rpm.
Always adjust 33
1/3 first, and always adjust 33 1/3 if 45 rpm
is to be adjusted
even
though
it might
be
accurate.
Connect
pin 7 of PA2007
to a_
oscilloscope
and make certain the frequency for 33 1/3 rpm
is 55.5Hz, and that for 45 rpm is 75Hz.
Buffer amp
to vcC2
Qi, Q2
2580372, 250945
PA2007
Connect to
oscilloscope
Fig. 11-4 Connect buffer amp
5 DIV
Fig. 11-5
Waveform
Fig. 11-6 VR1, VR2 position
» 1. Reti
s'ass
Port
Véri
piste
2. Gare
satic
VR4
poin
en 7
clen
pren
que
a la
(Fig
11.3
|
|
Lors
positio
matiqu
indicat
abimer
du rég]
1. Pla
50
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