– 16 –
6. After check, remove the lead wire connected in step 2.
Note :
•
Try to measure several times to make sure that the ratio
of A : B or B : A is more than 10 : 7.
•
Take sweep time as long as possible and light up the
brightness to obtain best waveform.
Adjustment Location : BD board (see page 16)
RF Level Check
+
–
BD board
TP (RF)
TP (VC)
oscilloscope
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 sig-
nal 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
Adjustment Location : BD board (see page 16)
E-F Balance Check
+
–
BD board
TP (TEO)
TP (VC)
oscilloscope
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 oscilloscope waveform is symmetrical on the
top and bottom in relation to 0 Vdc, and check this level.
specified level :
•
——————
×
100 = less than ± 7%
•
A+B= 300 ± 100 mVp-p
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] – Side B –
A-B
2 (A + B)
RF
FOK
RV101
IC101
IC102
TE1
FE1
FEO
RV103
TEO
VC
RV102
PCK
GND
IC104
symmetry
within 2.4 ± 0.7 Vp-p
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 be-
tween A and B. And confirm peak to peak level within 2.4 ± 0.7
Vp-p.
•
S-curve waveform
B
A
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.3
±
0.3Vp-p
level: 300 ± 100 mVp-p
0 V
A
B
•
Traverse waveform
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