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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. Adjustment procedure:
oscilloscope (DC range) BD board TP (RF) TP (VC)
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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 ± 0.7 Vp-p.
S-curve waveform symmetry
A within 2.4 ± 0.7 Vp-p B
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. RF Level Check
oscilloscope BD board
1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD board. 2. Ground display board IC701 pin @¢ with the lead wire. 3. 4. 5. 6. Turned power switch ON. (Stop mode) Put disc (YEDS-18) in and press the ^ button. Press the ^ button again. (Tracking servo ON) 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. Remove the lead wire connected in step2. � RF signal reference waveform (eye pattern)
VOLT/DIV: 200 mV TIME/DIV: 500 ns
TP (RF) TP (VC)
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Procedure: 1. Connect oscilloscope to test point TP (VC) and 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
When observing the eye pattern, set the oscilloscope for AC range and raise vertical sensitivity. S-Curve Check
oscilloscope BD board TP (FEO) TP (VC)
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Procedure: 1. Ground display board IC701 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 0V, and check this level.
Procedure: 1. Connect oscilloscope to test point TP (VC) and TP (FEO) on BD board. 2. Connect between test point TP (FOK) and Ground by lead wire. 3. Turned Power switch on. 4. Put disc (YEDS-18) in and turned Power switch on again and
