Technics SL-PJ37A

Measuring Instruments
* Playability test disc (SZZP1054C).
* Normal disc.
*
Dual-beam
oscilloscope
with
bandwidth
of
30MHz
or
better
(with
EXT
trigger
and
1:1
probe).
(1)
LASER
POWER
ADJUSTMENT
1. Connect the oscilloscope’s CH1 probe across (+) and (-)
of R3507 (Resistor) on the servo P.C.B.
2.
Switch
the
player
power
ON,
and
play
track
No.
1
on
the
test
disc
(SZZP1054C).
3. Adjust VR3520 so that the voltage is -50 + 2mV.
Oscilloscope setting:
20mV
(2)
FOCUS
OFFSET
ADJUSTMENT
1.
Connect
the
oscilloscope’s
CH1
probe
scross
R3562
(Resistor)
(+)
and
Jumper
(—)
on
the
servo
P.C.B.
2.
Switch
the
player
power
ON,
and
play
track
No.1
on
the
test
disc
(SZZP1054C).
3.
Adjust
VR3569
until
the
signal
amplitude
become
in
the
center
of
400mV.
Oscilloscope setting:
200 mV
INPUT ....... DC
SWEEP sso eed. Ps 5msec.
(3) PLL ADJUSTMENT
1.
Connect
CH1
of
the
oscilloscope
to
the
LINE
OUT
terminal
(either
of
Lch
or
Rch)
and
ground.
Oscilloscope
setting:
VOLT......
1V
SWEEP.....
msec.
INPUT
.....
DC
2. Switch the player power ON, and play track No. 6
(wedge 0.7mm) on the test disc (SZZP1054C).
3.
Check
the
waveform
displayed
on
the
oscilloscope
and
adjust
VR501
in
the
following
steps.
Step
1.
Turn
VR501
clockwise
slowly
and
ooserve
the
point
at
which
the
waveform
on
the
oscilloscope
begins
to
be
disturbed.
Step
2.
Turn
VR501
counterclockwise
slowly
and
observe
the
point
at
which
the
waveform
on
the
oscilloscope
begins to be disturbed.
Step
3.
Set
VR501
in
the
middle
between
the
points
observed in the above steps "1" and “’2".
_’
Noise
started
to
appear
in
output
sound
with
as
VR501
turned
counterclockwise.
’
is
2
Final setting point.
1
y
Noise
started
to
appear
in
output
sound
with
S VR501 turned clockwise.
Seegeae
el
Oe
5
NANT
TP
EN
ed
ik
lt
mVmAVEM
VRE
hea
Ge
ee
es
e OK
“
CHECK
OF
PLAY
OPERATION
AFTER
ADJUSTMENT
Checking Skip Search
1. Play an ordinary musical program disc.
2.
Press
the
skip
button
to
check
for
normal
skip
search
operation
(in
both
the
forward
and
reverse
directions).
Checking Manual Search
1. Play an ordinary musical program disc.
2.
Press
the
manual
search
button
to
check
for
smooth
manual
search
operations
at
either
low
or
high
speed
(in
both
the
forward
and
reverse
directions).
* Playability check by test disc
1.
Play
the
0.7
mm
black
dot
and
the
0.7
mm
wedge
on
the
defect
test
disc
(SZZP1054C)
and
verify
that
no
sound
skip
or
noise
occurs.
ae AD a