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• MEASUREMENTS AND ADJUSTMENTS
Control position and equipment used
•
Size
selector ....
.
.. 30
•
Oscilloscope
START POSITION ADJUSTMENT
1.
Put
on a 30 cm record.
2.
Turn the power switch "on'', and press the start button.
3. If the stylus drops too much inside or outside the
record,
adjust
the
start
position by turning
the
adjusting
screw.
•
Clockwise
................ Stylus drop position is
shifted
inside.
• Counterclockwise
.....
..
Stylus
drop position
is
shifted
outside.
CLOCK FREQUENCY ADJUSTMENT
1.
Remove the bottom
board.
2. Connect IC301 pins
11
, 12,
13, 14 to
ground.
Connect
IC301
pin 19 to g round for more than 15
msec;
then, d isconnect
it.
3.
Connect the oscilloscope to
IC
301 pin 5 (+) and
ground
(-)
.
4.
Turn the
power
switch
" on"
and adjust
VR301
so that
the output waveform cycle is
45±
1.Sµsec.
SERVO GAIN AND OFFSET VOLTAGE
ADJUSTMENT
1. Remove the dust
cover.
2.
Connect DC voltmeter to BT501 pin 2
and
pin
4.
3.
Turn the power switch
"on".
4. Turn the
VR501
so that the voltage is
3.6V
with
tonearm completely turned to the right (offset
angle
sensor "open")
.
(Servo gain
adjustment)
5. Return the tonearm to the center and make sure that
the voltage is
1.8V.
6. If the
voltage
is not 1.SV. adjust it
by
turning the offset
voltage adjusting
screw.
(Offset voltage
adjustment)
- 19-
•
DC electronic voltmeter
•
30 cm
record
Start
po~
~usting
screw
~
Set
Oscilloscope
0
IC301
Ground @pin
~
0
+
-
0000
<( <(
I
J
•
Oscilloscope setting
•
Waveform
Offset
VOLT
·
·
··· 1V
~
T=45±
1.5µsec.
SWEEP ....
. 10µsec.
JUUl
INPUT
.
..
..
DC
Set
DC voltmeter
Lr_::~J
!?I
•
Tonearm
turns
to
•
Tonearm
at center
the
right
r-f,\
6-y'
angle sensor
Tonearm
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