actuate the focus search. (actuate the focus search when disc
CD SECTION
table is moving in and out.)
Note:5. Check the oscilloscope waveform (S-curve) is symmetrical be-
1. CD Block basically constructed to operate without adjustment.tween A and B. And confirm peak to peak level within 2.4 ? 0.7
Therefore, check each item in order given.Vp-p.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.S-curve waveform
3. Use the oscilloscope with more than 10MW impedance.symmetry
4. Clean an object lens by an applicator with neutral detergent when
the signal level is low than specified value with the following
checks.A
within 2.4 ? 0.7 Vp-p
Focus Bias AdjustmentB
This adjustment is to be done when the optical block is replaced.
6. After check, remove the lead wire connected in step 2.
Adjustment procedure:
Note:? Try to measure several times to make sure that the ratio of
oscilloscopeA:B or B:A is more than 10:7.
(DC range)? Take sweep time as long as possible and light up the bright-
BD boardness to obtain best waveform.
TP (RF)+
TP (VC)�RF Level Check
oscilloscope
BD board
1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD
board.TP (RF)+
TP (VC)�
2. Ground display board IC701 pin @c with the lead wire.
3. Turned power switch ON. (Stop mode)Procedure:
4. Put disc (YEDS-18) in and press the ^ button.
1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD
5. Press the ^ button again. (Tracking servo ON)
board.
6. Adjust RV101 so that the oscilloscope waveform is as shown in
2. Turned Power switch on.
the figure below (eye pattern).
3. Put disc (YEDS-18) in and press the ^ button.
A good eye pattern means that the diamond shaA) in the pe (4. Confirm that oscilloscope waveform is clear and check RF sig-
center of the waveform can be clearly distinguished.
nal level is correct or not.
7. Remove the lead wire connected in step2.
Note:Clear RF signal waveform means that the shaA� can be pe O
clearly distinguished at the center of the waveform.
? RF signal reference waveform (eye pattern)
RF signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.3 ? 0.3Vp-plevel:
1.3 ? 0.3Vp-p
When observing the eye pattern, set the oscilloscope for AC
range and raise vertical sensitivity.
E-F Balance (Traverse) Check
S-Curve Checkoscilloscope
(DC range)
oscilloscope
BD board
BD boardTP (TEO)+
TP (VC)�
TP (FEO)+
TP (VC)�
Procedure:
1. Ground display board IC701 pin @c with the lead wire.
Procedure:2. Connect oscilloscope to test point TP (TEO) on BD board.
1. Connect oscilloscope to test point TP (VC) and TP (FEO) on3. Turned Power switch on.
BD board.
4. Put disc (YEDS-18) in and press the ^ button.
2. Connect between test point TP (FOK) and Ground by lead wire.
5. Confirm that the oscilloscope waveform is symmetrical on the
3. Turned Power switch on.
top and bottom in relation to 0V, and check this level.
4. Put disc (YEDS-18) in and turned Power switch on again and
� 12 � |
ACEC
