CDP-XB740, CDP-XB740E - Sony Audio Service Manual (repair manual). Page 10

10

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.

Procedure :
1. Connect oscilloscope to test point TP (FE) on BD board.
2. Connect the test point JW003 (ADJ) on MAIN board to the

ground with a lead wire.

3. Turn ON the power.
4. Put disc (YEDS-18) in press  H  (play) button.
5. When the  11  button of the remote commander is pressed, the S

curve will be output continuously.

6. Check the oscilloscope waveform (S-curve) is symmetrical

between A and B. And confirm peak to peak level within 3
Vp-p.

S-curve waveform

7. After check, remove the lead wire connected in step 2.

• 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.

+ 1.5
– 1

±

Procedure :
1. Connect oscilloscope to test point TP (FE) on BD board.
2. Connect between test point TP (FEI) 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 3.8 

±

 1

Vp-p.

7. After check, remove the lead wire connected in step 2 and 3.

• 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.

±

S-curve waveform

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 sig-

nal level is correct or not.

A clear RF signal waveform means that the shape “

◊

” can be clearly

distinguished at the center of the waveform.

       RF signal waveform

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  X  (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%