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(
(5)
.
ADJUSTMENTS
1 . Sled
Offset Adjustment
Adjust the VR103 (SLD OFFSET) so
that
the DC voltage
between TP120 and TP121 to DC OV
± 0.25V.
2.
Tracking Balance
Adjustment
Adjust the VR301 (TE BAL) so that the center of the
waveform of the tracking error signal (TP304) when the
tracking is OFF is aligned with the center of the waveform
of the tracking error signal when the tracking is ON.
3. FE
Bias
Adjustment
Adjust the VR302
(FE.
BIAS) so that the jitter meter to its
smallest value.
4. Tracking Gain Adjustment
Waveform measurement
points:
T P107 (TE IN)
TP109 (TE
2)
Input l.4kHz, lOOm V to the above measurement points apd
adjust VR101 so that the Lissajous waveform is
symme.trical about the X axis and Y axis. (refer to Fig. 1)
i
.
!••
DR-U104X
5
.
Focus Gain Adjustment
W aveform
mea
surement points: TP110 (FE IN)
T P138 (FE)
Input l. lkHz, lOOm V to the above measurement points and
adjust VR102
'
so that the Lissajous waveform is
symmetrical about the X axis and Y
axis.
(refer to
Fig.
1)
For
the
gain adjustments in
4.
Tracking Gain and
5.
Focus
Gain,
TRK ERR and FCS ERR waveform measurements
are
made
through a filter, as shown in the diagram
below.
33k
ERR~
Oscil lator
1000p
~Standard
voltage: 2.75±0.2V
(IC301, Pin 12, etc .)
Higher Gain
Optimum Gain
Lower Gain
MAI
N
PCB UNIT
~
o
Fig. 1
Lissajous Waveform
.,...,.._,.
-
0
o"lll
MAIN PCB
VR103
u .f?w
TP121
0
0
TP120
127-5823-61 •MY·
Ol!lllJA
TP138
ll
-
0
VR102
9:~
VR10
1
TP1091J,.._
TP107
.
!?
TP11
0
P" ..
"":--IC301
VR302'--
~
o TP304
,!..
VR301
Fig
. 2
Adjustment and Measurement points
1-7
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