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Text excerpt from page 20 (click to view)
CD SECTION NOTE :
1. CD Block 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 the oscilloscope with more than 10M� impedance. 4. Clean an object lens by an applicator with neutral detergent when the signal level is low than specified value with the following checks. Focus Bias Adjustment This adjustment is to be done when the optical block is replaced.
2. Connect between test point TP (FOK) and GND by lead wire. 3. Turned 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 between A and B. And confirm peak to peak level within 2.4 ± 0.7Vp-p.
S-curve waveform symmetry
1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD (CD) board. 2. Connect TP ADJ (IC301 @� pin) to ground with lead wire on Main board. 3. Turned power switch ON. (Stop mode) 4. Put disc (YEDS-18) in and press the ^ button. 5. Press the ^ button (Tracking servo ON). 6. Adjust RV101 so that the oscilloscope waveform is as shown in the figure below (eye pattern). A good eye pattern means that the diamond shape ( ) in the center of the waveform can be clearly distinguished. 7. After adjustment,remove the lead wire connected in step 2.
r
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 bright ness to obtain best waveform. Adjustment Location : BD (CD) board. (see page 13) RF Level Check
oscilloscope BD (CD) board TP (RF) TP (VC)
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Procedure : 1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD (CD) 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.
r
When observing the eye pattern, set the oscilloscope for AC range and raise vertical sensitivity. Adjustment Location : BD (CD) board. (see page 13) S-Curve Check
oscilloscope BD (CD) board TP (FEO) TP (VC)
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Adjustment Location : BD (CD) board. (see page 13)
Procedure : 1. Connect oscilloscope to test point TP (VC) and TP (FEO) on BD (CD) board.
