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LD V4300D
5. FOCUS ERROR BALANCE ADJUSTMENT
• Purpose: To set the object lens to its optimum position so that it works
optimally
with
the focus servo while
playing a disc.
• Symptoms when incorrectly adjusted:
Crosstalk.
Measurement equipment
&
Jigs
• TV monitor
• Test disc: GGV1003
•
Oscilloscope
Adjusting procedure
Measurement equipment
connecting points
• TV
monitor:
Connect to
the video
output
terminal
of the
player.
•
Oscmoscope:
In
the
FTSB
assembly
CHI: Between TRKG
ERROR (TPI
-9)
and
GND
I. Play the test disc in the service
mode.
2. Around
the position of frame
Nl,000,
open
the
track-
ing servo,
and write down the error level
(A)
at
this
time. (Fig.
5-1)
FOCS
BAL should
be set to
-1 •.
3. Set
the player to the
normal mode and
search
for
frame
#115.
Select ff0'' for FOCS BAL. {When FOCS BAL
is
set
to
"1"',
the trigger
error
will
be
maximum.
Use
VR.6 for
adjustment.)
4.
Observe
the
crosstalk
appearing
on
both
the
left
and
right
sides
of
the
TV screen, and
check
that
the
cross-
talk is
minimum and symmetrical.
If
crosstalk seems
to be in good condition, this adjustment
is
finished.
5. If the
crosstalk
observed above is not acceptable, read-
just VR7 in the FTSB assembly to get minimum
cross-
Adjustment diagram
FTSB assembly
O
VR7
Qi,!
I
CN4
Player condition
Adjusting points
•
Service
mode:
• VR7 in the FTSB
• Play mode
assembly
• Tracking
servo
loop
open·
•
Tilt
servo
OFF
• Normal
mode
•
Still mode
•
Tilt
servo OFF
talk. (Fig. 5-3)
6. Set the player to
the_
service
mode again, open the
tracking servo
around
frame
#
1,000 and write down
the error level (B)
at
this
time. (Fig.
5-2)
7.
When level dHrerence
between
A
and
Bis within
300/o
(BIA
~
0.7), this
adjustment
is
finished.
8.
If
the
level
difference
is
more
than
30070,
return
VR7
so
that
it
becomes
within
30070.
9.
Set
the
player
to the
normal
mode again and search
for frame
#
I
15,
and
check that the
crosstalk
is
mini-
mum and
symmertrial.
(Fig.
5-3)
JO.If
the
crosstalk
seems
in
good
condition,
t
his
adjustment is finished.
I
f
it
is
not
acceptable, perfonn
item "4. Pick-up
tracking
and tangential direction
inclination
adjustment"
again.
(See
page 112)
_j
-·7
Fig. 5
-
2
1···-·
9°
G
TP1
Q
~
ot;J
CJ
I)
w
0
0
0
0
0
0
nil~[IJ
~
l a ) §
Cross1alk
on
the
screen
MiNmum
c-routalk
F,g.
5-
4
Fig. 5-3
10B
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