SECTION 6
ELECTRICAL ADJUSTMENTS
CD SECTION
Note:
1.CD Block is basically designed to operate without adjustment. Therefore, check each item in order given.
2.Use
3.Use an oscilloscope with more than 10MΩ impedance.
4.Clean the object lens by an applicator with lens cleaning liquid when the signal level is low than specified value with the fol- lowing checks.
5.Adjust the focus bias adjustment when optical block is replaced.
Focus Bias Adjustment
Perform this adjustment when the optical
oscilloscope
BD (CD) board |
|
TP (RF) | + |
TP (VC) | – |
Procedure:
1.Connect oscilloscope to test point TP (RF).
2.Turned Power switch on.
3.Put disc
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
level : 1.3 ± 0.3
S Curve Check
oscilloscope
BD (CD) 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
5.Check the oscilloscope waveform
symmetry
A
within 2.4 ± 0.7
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 bright- ness to obtain best waveform.
RF Level Check
oscilloscope
BD (CD) board |
|
TP (RF) | + |
TP (VC) | – |
Procedure :
1.Connect oscilloscope to test point TP (RF) on BD board.
2.Turned Power switch on.
3.Put disc
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 VOLT/DIV: 200 mV TIME/DIV: 500 nS
level : 1.3 ± 0.3
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