| |
SECTION 5 | Ver 1.1 2001.07 |
ELECTRICAL ADJUSTMENTS |
|
Note:
1.CD Block is basically designed to operate without adjustment. There- fore, 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 neutral detergent when the signal level is low than specified value with the following checks.
S Curve Check
Connection:
oscilloscope
BD board
TP (FE1) 
+
TP (VC) 
–
Procedure:
1.Set the test disc
2.Connect an oscilloscope to test point TP (FE1) and TP (VC) on the BD board.
3.Connect between test point TP (ADJ) on the MAIN board and GND by lead wire.
4.Press the [POWER] button to turn the power on and enter the ADJ mode.
Then playback the number two track automatically, press the x button to stop the playback.
5.Press the [CHECK] button actuate the focus search. (actuate the focus search when disc table is moving in and out)
6.Check the oscilloscope waveform
symmetry
A
within 2 ± 1
B
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.
Checking Location: BD board
RFDC Level Check
Connection:
oscilloscope
BD board |
|
TP (RFDC) | + |
TP (VC) | – |
Procedure:
1.Set the test disc
2.Connect an oscilloscope to test point TP (RFDC) and TP (VC) on the BD board.
3.Connect between test point TP (ADJ) on the MAIN board and GND by lead wire.
4.Press the [POWER] button to turn the power on and enter the ADJ mode, then playback the number two track automatically.
5.Confirm that oscilloscope waveform is clear and check the level
of between RFDC top and VC is correct or not.
Note: A clear RFDC signal waveform means that the shape “◊ ” can be clearly distinguished at the center of the waveform.
RFDC signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.15 ± 0.35
VC
Checking Location: BD board
RFAC Level Check
Connection:
oscilloscope
BD board |
|
TP (RFAC) | + |
TP (VC) | – |
Procedure:
1.Set the test disc
2.Connect an oscilloscope to test point TP (RFAC) and TP (VC) on the BD board.
3.Connect between test point TP (ADJ) on the MAIN board and GND by lead wire.
4.Press the [POWER] button to turn the power on and enter the ADJ mode, then playback the number two track automatically.
5.Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note: A clear RFAC signal waveform means that the shape “◊ ” can be clearly distinguished at the center of the waveform.
RFAC signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.35 ± 0.4
Checking Location: BD board
13