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LD-V4300D
2. GRATING TEMPORARY ADJUSTMENT AND TRACKING (TRKGI BALANCE ADJUSTMENT
• Purpose:
Set
the
laser
beam
which is divided
into three by the grating
so
that
it is directed
to the
optimum
posi-
tion on the
playback
track.
Set
the offset
voltage of
the
tracking
servo
to O
V.
•
Symptoms
when incorrectly adjusted:
Di~ play
impossible. Track jumping.
Measurement equipment
Measurement equipment
Player condition
Adjusting
points
&
jigs
connecting
points
•
Screwdriver
(Oat
bladed)
•
Oscillosoope:
Jn
FTSB
•
Service mode:
•
Grating
adjustment screw
• Oscilloscope
assembly
•
Play
mode
in
the
pick•UP assembly
•
Test
disc:
GGV1003
CHl:
Between
TRKG
•
Tracking
servo loop
open
•
VR2
nnd
VR6 in
FTSB
ERROR
(TPl-
9) and
GND
•
Tilt
servo
OFF
assembly
Adjusting
procedure
[Grating temporary adjustment]
.
reverse key instead
o
f
holding
with your
hand.)
l
.
With
the player set
horiwntally,
play the
test
disc.
7. In this
condition, when
the grating
adjustment screw
2.
Press the DISPLAY key so that 1he
frame
number
is
is turned
counterclockwise
slowly.
the amplitude of
the
displayed
on
the TV
screen.
tracking
error waveform
gradually becomes larger.
Set
3. Open the
TRKG servo loop.
to
the
position where the waveform
amplitude
becomes
4, Using the SCAN key, move the pick.up
to
a
position
maximum.
(Photo 2)
around
frame
#
20000.
8.
Set
the tracking error
to
maximum by
using
VR6
S. Connect
the oscilloscope to
TPl
-
9
(TRKG
error)
(FOCS BAL). Note
that
"1~
should
be
selected for
to
observe the waveforms.
FOCS
BAL
shown
on the
monitor. Change it
to
"O"
6. l
nserl
the
flat bladed
8
screwdriver (small)
into
the
(VR7)
after
adjustmejnt.
grating
adjus1ment
hole
horizon1ally (Fig. 2-
1)
.
9. Close
the
Tracking servo to make sure
that
a picture
on
When the
grating
adjustment screw
is turned,
the
the
screen
is
normal.
tracking error
waveform alternates
belween
large
and
[TRKG (Tracking) balance
adjus
tment]
5mall. After the waveform
amplitude
becomes
small,
I.
Set the
player
lo
the
stop mode
and raise it so it is verti·
find
the position where the
waveform shows a smooth
cal,
then play
the
lest disc
in
the service mode.
envelope. (Photo
1) (This
status
is
called
the
"on-
(Note:
If
the disc
cannot be played in
this
condition,
set
track"
posilion.)
the player
horizon
tally and engage
the service
(When adjusting
the grating
with
1he
small screwdriver
mode
to start
p laying
the
disc,
and
then raise the
(Oat-bladed),
since
the
pick.
up
assembly
tends
to
shift
left side of
ih
e
p
layer
slowl
y,
so
it
is
vertica/.J
toward
the inside
of
the
disc, perform adjustment
while
holding
it
with your
hand. If
a
remote
control
2. Set
the oscilloscope's
GND point
to
the
center of
the
is
available,
rock
the pick.up
by
pressing the
multi-
oscilloscope screen.
l
.
Adjust VR2
in
the
FTSB
assembly
so that
the
positive
:
amplitude
(A) and
the negative
amplitude (B)
becomes
equal. (P hoto
2)
Adjustme
nt
diagra
m
FTSB
ass•mbly
VR2f&l
'l,i.,
ell
Oscilloscope
~ ,
, . i ~
8
r;J
0
CHI
l
D~
C
C
CJD
oo
0
~
~ l a
1
0
4
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