SECTION 6
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
oscilloscope
BD board |
|
TP (FE) | + |
TP (VC) | – |
Procedure :
1.Press the I/u button and turn ON the power supply.
2.Open the front cover, and press the [PLUSÊONE] button.
3.Set the disc
4.Close the front cover, and chuck the disc.
5.Press the I/u button and turn OFF the power.
6.Connect the oscilloscope to TP (FE) of the BD board.
7.Connect TP (ADJ) of the MAIN board and connect TP (GND) with a lead wire.
8.Press the I/u button and turn ON the power.
9.The first track will be played back automatically. When the [CHECK] button is pressed,
10.Check the oscilloscope waveform
symmetry
A
within 1.8 ± 0.6
B
11. Turn OFF the power, and remove the lead wire connected at step 7.
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.
RF Level Check
oscilloscope
(AC range)
BD board |
|
TP (RF) | + |
TP (VC) | – |
Procedure :
1.Press the I/u button and turn ON the power supply.
2.Open the front cover, and press the [PLUSÊONE] button.
3.Set the disc
4.Close the front cover, and chuck the disc.
5.Press the I/u button and turn OFF the power.
6.Connect the oscilloscope to TP (RF) of the BD board.
7.Connect TP (ADJ) of the MAIN board and connect TP (GND) with a lead wire.
8.Press the I/u button and turn ON the power.
9.Playback the fifth track of the disc.
10.Confirm that oscilloscope waveform is clear and check RF signal level is correct or not.
11.Turn OFF the power, and remove the lead wire connected at step 7.
Note : A clear RF signal waveform means that the shape “ ◊” can be clearly distinguished at the center of the waveform.
RF signal waveform
VOLT/DIV : 200 mV
TIME/DIV : 500 ns
level: 1.8
E-F Balance (Traverse) Check
The procedure for this checking method differs for when a gen- eral remote control unit is used and not used.
oscilloscope
BD board |
|
TP (TE) | + |
TP (VC) | – |
When a general remote commander is used:
1.Press the I/u button and turn ON the power supply.
2.Open the front cover, and press the [PLUSÊONE] button.
3.Set the disc
4.Close the front cover, and chuck the disc.
5.Press the I/u button and turn OFF the power.
6.Connect the oscilloscope to TP (TE) of the BD board.
7.Connect TP (ADJ) of the MAIN board and connect TP (GND) with a lead wire.
8.Press the I/u button and turn ON the power.
9.Playback the fifth track of the disc.
10.Press the [3] button on the remote commander. (The tracking servo and the sledding servo are turned OFF.)
11.Check the level B of the oscilliscope's waveform and the A (DC voltage) of the center of the Traverse waveform. Confirm the following :
A/B x 100 = less than ± 10%
| Center of the |
Traverse waveform | waveform |
| B |
0 V | A (DC voltage) |
| |
| level: 0.9 ± 0.45 |
12.Press the [8] button on the remote control unit. (The tracking servo and sledding servo are turned ON.) Confirm the C (DC voltage) is almost equal to the A (DC voltage) is step 11.
Traverse waveform
| C (DC |
0 V | voltage) |
Tracking servo | Tracking servo |
Sled servo | Sled servo |
OFF | ON |
13.Turn OFF the power, and remove the lead wire connected at step 7.
