Table of Contents
Advertisement
Note:
1. CD Block is basically designed to operate without adjustment. There-
fore, 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 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
BD board
TP (FE1)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (FE1) on BD board.
2. Connect test point TP (ADJ) on MAIN board to ground with
lead wire.
3. Turn I/u button on to set the ADJ mode.
4. Put disc (YEDS-18) in and playback.
[CHECK]
Press the
button.
5. Check the oscilloscope waveform (S-curve) is symmetrical be-
tween A and B. And confirm peak to peak level within 3 ± 1
Vp-p.
S-curve waveform
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.
RF Level Check
BD board
TP (RFO)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (RFO) on BD board.
2. Turn I/u button on.
3. Put disc (YEDS-18) in to play the number five track.
4. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
ELECTRICAL ADJUSTMENTS
oscilloscope
+
–
symmetry
A
within 3 ± 1 Vp-p
B
oscilloscope
(AC range)
+
–
SECTION 6
Note: A clear RF signal waveform means that the shape "◊" can be clearly
distinguished at the center of the waveform.
RF signal waveform
E-F Balance Check
BD board
TP (TE)
TP (VC)
Procedure :
1. Connect oscilloscpe to test point TP (TE) on BD board.
2. Connect the test point TP (ADJ) on MAIN board to the ground
with a lead wire.
3. Turn the I/u button on to set the ADJ mode.
4. Put disc (YEDS-18) in to play the number five track.
[GROUP 3]
5. Press the
ding servo are turned OFF.)
6. 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 ± 22%
Traverse waveform
0 V
[GROUP 8]
7. Press the
ding servo are turned ON.) Confirm the C (DC voltage) is
almost equal to the A (DC voltage) is step 6.
Traverse waveform
0 V
8. Disconnect the lead wire of TP (ADJ) connected in step 1.
– 19 –
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.2
oscilloscope
+
–
button. (The tracking servo and the sled-
Center of the waveform
B
level: 1.3 ± 0.6 Vp-p
button. (The tracking servo and sled-
Tracking servo
Tracking servo
Sled servo
Sled servo
OFF
ON
+0.25
Vp-p
–0.20
A (DC voltage)
C (DC
voltage)
Advertisement
Table of Contents
