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– 15 –
4. Put disc (YEDS-18) in and turned Power switch on again and
actuate the focus search. (actuate the focus search when disc table
is moving in and out.)
5. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within
2.4±0.7Vp-p.
S-curve waveform
symmetry
within 2.4
±
0.7Vp-p
A
B
6. After check, remove the lead wire connected in step 2.
Note :
r
Try to measure several times to make sure that the ratio of
A : B or B : A is more than 10 : 7.
r
Take sweep time as long as possible and light up the brigh-
ness to obtain best waveform.
Adjustment Location : BD board. (see page 15)
RF Level Check
+
–
oscilloscope
TP (RF)
BD board
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in and press the
(
button.
4. Confirm that oscilloscope waveform is clear and check RF signal
level is correct or not.
Note :
Clear RF signal waveform means that the shape “
◊
” can be clearly
distinguished at the center of the waveform.
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.3
±
0.3Vp-p
Adjustment Location : BD board. (see page 15)
E-F Balance Check
+
–
oscilloscope
(DC range)
TP (TEO)
TP (VC)
BD board
Procedure :
1. Ground main board IC101 (pin
(£
) with the lead wire.
2. Connect oscilloscope to test point TP (TEO) on BD board.
3. Turned Power switch on.
4. Put disc (YEDS-18) in and press the
(
button.
5. Confirm that the osilloscope waveform is symmetrical on the
top and bottom in relation to 0V, and check this level.
Traverse waveform
specified value :
r
A–B
2 (A+B)
X100 = less than
±
7%
r
A+B = 300
±
100mVp-p
level : 300
±
100mVp-p
A
B
0V
6. Remove the lead wire connected in step 1.
Focus/Tracking Gain Adjustment (RV102, RV103)
This gain has a margin, so even if it is slightly off. There is no prob-
lem.
Therefore, do not perform, this adjustment.
Please note that it should be fixed to mechanical center position when
you moved and do not know original position.
Adjustment Location :
[
BD BOARD
] –
Conductor side
–
IC102
FEI
TEI
FOK
IC101
RF
RV101
RV102
IC104
FEO
TEO
VC
PCK
GND
RV103