CD SECTION
Note: 1. CD Block is basically designed 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 10 M� impedance. 4. Clean the object lens by an applicator with lens cleaning liquid when the signal level is low than specified value with the following checks. 5. Adjust the focus bias adjustment when optical block is replaced. Focus Bias Adjustment Perform this adjustment when the optical pick-up has been replaced or repaired.
oscilloscope BD (CD) board TP (RF) 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 between A and B. And confirm peak to peak level within 2.4 ± 0.7 Vp-p. S-curve waveform
symmetry
Procedure: 1. Connect oscilloscope to test point TP (RF). 2. Turn Power switch on. 3. Put disc (YEDS-18) in and playback. 4. Adjust RV101 so that the waveform is clear. (Clear RF signal waveform means that the shape ��� can be clearly distinguished at the center of the waveform.) 5. After adjustment, check the RF signal level. � RF signal VOLT/DIV: 200 mV TIME/DIV: 500 nS
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 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 brightness to obtain best waveform.
Procedure : 1. Connect oscilloscope to test point TP (RF) on BD (CD) board. 2. Turn Power switch on. 3. Put disc (YEDS-18) in and playback. 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.
