Electrical Block Checking - Sony CDP-CX200 Service Manual

5-2. ELECTRICAL BLOCK CHECKING

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 (FE 1)
TP (VC)
Procedure :
1. Connect oscilloscope to test point TP (FE 1) on BD board.
2. Connect test point TP301 (ADJ) on MAIN board to ground with
lead wire.
3. Turn Power switch on to set the ADJ mode.
4. Put disc (YEDS-18) in and playback.
Press the CHECK 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 bright-
ness 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 Power switch on.
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.
oscilloscope
symmetry
A
within 3 ± 1 Vp-p
B
oscilloscope
— 19 —
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 TP301 (ADJ) on MAIN board to the ground
with a lead wire.
3. Turn the Power switch on to set the ADJ mode.
4. Put disc (YEDS-18) in to play the number five track.
5. Press the "BLOCK3" button. (The tracking servo and the sled-
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
0V
7. Press the "BLOCK 8" button. (The tracking servo and sledding
servo are turned ON.) Confirm the C (DC voltage) is almost equal
to the A (DC voltage) is step 6.
Traverse waveform
0V
Tracking servo
Sledding servo
OFF
8. Disconnect the lead wire of TP301 (ADJ) connected in step 1.
VOLT/DIV : 200mV
TIME/DIV : 500ns
+0.25
level : 1.2 Vp-p
–0.20
oscilloscope
Center of the waveform
B
A (DC voltage)
level : 1.3 ± 0.6 Vp-p
C (DC
voltage)
Tracking servo
Sledding servo
ON