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SECTION 4
ELECTRICAL ADJUSTMENTS
oscilloscope
BD board
TP (RF)
TP (VC)
CD SECTION
Note:
1. CD Block is basically constructed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M impedance.
4. Clean the object lens by an applicator with neutral detergent when
the signal level is low than specified value with the following
checks.
S Curve Check
oscilloscope
BD board
TP (FEO)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (FOK) and Ground by lead wire.
3. Turn Power switch on.
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 3 ± 1Vp-p.
S-curve waveform
within 3 ± 1 Vp-p
symmetry
B
A
6. After check, remove the lead wire connected in step 2.
Note:
• Try to measure several times to make sure than the ratio of
A : B or B : A is more than 10 : 7.
• Take sweep time as long as possible and light up the bright-
ness to obtain best waveform.
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
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
VOLT/DIV: 200 mV
TIME/DIV: 500 nS
level: 1.1 ± 0.3 Vp-p
E-F Balance (1 Track Jump) check
oscilloscope
BD board
TP (TEO)
TP (VC)
Procedure:
1. Connect oscilloscope to test point TP (TEO) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in to play the number five track.
4. Press the “
P
(Pause)” button.
5. Check the level B of the oscilloscope's waveform and the A (DC
voltage) of the center of the Traverse waveform.
Confirm the following:
• A/B x 100 = less than ± 7 (%)
1 track jump waveform
Center of the waveform
B
A (DC voitage)
Symmetry
level : 500 mV ± 100 mVp-p
Adjustment Location:
[BD BOARD] (Conductor Side)
CNU102
TP
(FOK)
TP
(RF)
0V
IC102
IC101
IC103
TP
(TEO)
RF Level Check
TP
(VC)
TP
(FEO)
TP
(GND)
CNU101
