Electrical Block Checking - Sony CDP-CA70ES Service Manual

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 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 between test point TP (FE1) and TP (VC) by lead wire.
3. Connect both ends of TP R151 of the BD board to the lead wire.
4. Turn ON the power.
5. Put disc (YEDS-18) in and actuate the focus search. (actuate the
focus search when disc table is moving in and out.)
6. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 4.5 ± 1
Vp-p.
S-curve waveform
7. After check, remove the lead wire connected in step 2 and 3.
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 (RF)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turn ON the power.
3. Put disc (YEDS-18) in to play the number five track.
4. Confirm that oscilloscope waveform is clear and check RF signal
level is correct or not.
SECTION 5

ELECTRICAL BLOCK CHECKING

oscilloscope
symmetry
A
Within 4.5 ± 1 Vp-p
B
oscilloscope
— 15 —
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 (1 Track Jump) Check
(without general remote commander)
BD board
TP (TE)
TP (VC)
Procedure :
1. Connect oscilloscpe to test point TP (TE) on BD board.
2. Turn ON the power.
3. Put disc (YEDS-18) in to play the number five track.
4. Press the P (Pause) button. (Becomes the 1 track jump mode)
5. 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%
0V
+ 0.7
level : 1.3
– 0.6
1 track jump waveform
BD board
TP (TE)
TP (VC)
E-F Balance Check (With general remote commander)
Procedure :
1. Turn ON the power, put disc (YEDS-18), turn OFF the power.
2. Connect the test point TP2 (ADJ) on MAIN board to the ground
with a lead wire.
3. Connect oscilloscope to test point TP (TE) on BD board.
4. Turn the Power switch on to set the ADJ mode, automaticaly
play the number five track.
5. Press the 3 button. (The tracking servo and the sledding servo
are turned OFF.)
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.2 ± 0.2 Vp-p
oscilloscope
Center of the waveform
B
A (DC voltage)
Vp-p
symmetry
oscilloscope