Pioneer LD-V4300D Service Manual page 73
Laserdisc player
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Also See for LD-V4300D:
- Service manual (99 pages) ,
- Operating instructions manual (23 pages)
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2. GRATING TEMPORARY ADJUSTMENT AND TRACKING (TRKG) BALANCE ADJUSTMENT
• P
urpose: Set the laser beam which is divided into three by the
grating
so that
it is
directed
to
the optimu
m
posi-
tion
on the playback track
.
Set the offset voltage of
the
tracking
servo to
O
V.
•
Symptoms when incorrectly adjusted: Disc play impossible. Track
jumping.
Measurement
equipment
&
jigs
•
Screwdriver (flat bladed)
•
Oscilloscope
•
Test disc: GGV1003
Adjusting procedure
Measurement equipment
connecting points
•
Oscilloscope:
In
FTSB
assembly
CHI: Between TRKG
ERROR (TPl-9) and
GND
[Grating temporary
adjustment)
I. With the player
set
horizontally, play the test
disc.
2.
Press the DISPLAY
key so that the frame
number
is
displayed on
the
TV
screen.
3.
Open the TRKG
servo
loop.
4. Using the SCAN key, move the pick-up to
a
position
around
frame
#
20000.
5.
Connect the oscilloscope to T
P
l-9 (TRKG error)
to observe the
waveforms.
6. lnsen the flat bladed
8
screwdriver
(small) into the
grating
adjustment
hole horizontally (Fig.
2-1).
When the
grating
adjustment
screw
is turned,
the
tracking error waveform
alternates
between
large and
small.
After the waveform amplitude becomes
small,
find the position
where the waveform shows
a
smooth
envelope.
(Photo
1)
(This status
is
called
the
"on-
track" position .)
(When
adjusting
the grating with the small screwdriver
(flat-bladed),
since
the pick-up assembly
tends
to
shift
toward the
inside of the
disc, perform
adjustment
while holding it
with your
hand. If
a
remote control
is
available,
rock the pick-up by pressing the
multi-
Player condition
•
Service mode:
•
Play
mode
•
Tracking
servo
loop open
•
Tilt servo
OFF
Adjusting points
•
Grating adj
ustment
screw
in
the pick-up assembly
•
VR2 and VR6
in FTSB
assembly
reverse
key instead of holding with your hand.)
7.
In
this condition, when
the
grating
adjustment screw
is
turned counterclockwise slowly,
the amplitude of the
tracking error waveform gradually
becomes larger. Set
to the
position
where
the
waveform
amplitude becomes
maximum
.
(Photo 2)
8.
Set the tracking error to maximum
by using VR6
(FOCS BAL). Note that
"1"
should be selected
for
FOCS
BAL
shown on the monitor.
Change
it
to "O"
(VR7) after adjustmejnt.
9.
Close the Tracking servo to
make
sure
that a picture
on
the
screen
is normal.
[TRKG
(Tracking)
balance
adjustment]
I. Set the player to the
stop mode
and raise
it so
it is verti-
cal,
then
play
the
test disc
in
the
service
mode.
(Note:
If
the disc cannot be played in this
condition,
set
the player horizontally and engage the service
mode to start playing the disc,
and
then raise
the
left side of the player slowly, so it is vertical.)
2.
Set the
oscilloscope's
GND point to
the center
of the
oscilloscope
screen.
3. Adjust VR2 in
the
FTSB
assembly
so
that the positive
amplitude (A)
and the negative
amplitude
(B) becomes
equal. (Photo
2)
Adjustment diagram
FTSB
assembly
VR2~
D
~
®
c
l
O ~ p e
,,,i·
0
~
0
~
0
CH1:::
-
~
•~
0
•
D
0
0
0
I
0
~
§;J§]
104
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