Sony CDP-CX225, Service Manual

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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 10M
Ω
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
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
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.
Note: A clear RF signal waveform means that the shape “
◊
” can be
clearly distinguished at the center of the waveform.
RF signal waveform
oscilloscope
BD board
BD board
TP (RF)
TP (VC)
oscilloscope
level : 1.2 Vp-p
VOLT/DIV : 200mV
TIME/DIV : 500ns
+0.25
–0.20
symmetry
within 3 ± 1 Vp-p
A
B
5-2. ELECTRICAL BLOCK CHECKING
TP (FE 1)
TP (VC)
E-F Balance Check
oscilloscope
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.)
Center of the waveform
B
level : 1.3 ± 0.6 Vp-p
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
8. Disconnect the lead wire of TP301 (ADJ) connected in step 1.
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
A (DC voltage)
Tracking servo
Sledding servo
OFF
Tracking servo
Sledding servo
ON
C (DC
voltage)
0V