Sony CDP-CX57 - 50 Disc Cd Changer, Service Manual

– 17 –

SECTION 6

ELECTRICAL ADJUSTMENTS

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 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

11. Turn OFF the power, and remove the lead wire connected at

step 7.

Note :

A clear RF signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

Procedure :
1. Press the

I

/

u

button and turn ON the power supply.

2. Open the front cover, and press the 

[PLUS ONE]

 button.

3. Set the disc (YEDS-18) into the “PLUS ONE” slit.
4. Close the front cover, and chuck the disc.
5. Press the

I

/

u

button and turn OFF the power.

6. Connect the oscilloscope to TP (FE) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)

with a lead wire.

8. Press the

I

/

u

button and turn ON the power.

9. The first track will be played back automatically. When the

[CHECK]

 button is pressed, “S-JI mode” will be displayed on

the fluorescent indicator tube, and focus search will be repeated.

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

tween A and B. And confirm peak to peak level within 1.8 ±
0.6 Vp-p.

11. Turn OFF the power, and remove the lead wire connected at

step 7.

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

Procedure :
1. Press the

I

/

u

button and turn ON the power supply.

2. Open the front cover, and press the 

[PLUS ONE]

 button.

3. Set the disc (YEDS-18) into the “PLUS ONE” slit.
4. Close the front cover, and chuck the disc.
5. Press the

I

/

u

button and turn OFF the power.

6. Connect the oscilloscope to TP (RF) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)

with a lead wire.

8. Press the

I

/

u

button and turn ON the power.

9. Playback the fifth track of the disc.
10. Confirm that oscilloscope waveform is clear and check RF

signal level is correct or not.

E-F Balance (Traverse) Check

The procedure for this checking method differs for when a gen-
eral remote control unit is used and not used.

When a general remote commander is used:
1. Press the

I

/

u

button and turn ON the power supply.

2. Open the front cover, and press the 

[PLUS ONE]

 button.

3. Set the disc (YEDS-18) into the “PLUS ONE” slit.
4. Close the front cover, and chuck the disc.
5. Press the

I

/

u

button and turn OFF the power.

6. Connect the oscilloscope to TP (TE) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)

with a lead wire.

8. Press the

I

/

u

button and turn ON the power.

9. Playback the fifth track of the disc.
10. Press the 

[3]

 button on the remote commander. (The tracking

servo and the sledding servo are turned OFF.)

11. 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 ± 10%

BD board

TP (FE)

TP (VC)

+
–

oscilloscope

symmetry

S-curve waveform

within 1.8 

±

 0.6 Vp-p

A

B

BD board

TP (RF)

TP (VC)

+
–

oscilloscope

(AC range)

level: 1.8      Vp-p

+0.3
–0.2

VOLT/DIV : 200 mV
TIME/DIV : 500 ns

RF signal waveform

BD board

TP (TE)

TP (VC)

+
–

oscilloscope

Center of the 
waveform

Traverse waveform

B

A (DC voltage)

0 V

level: 0.9 

±

 0.45 Vp-p

Traverse waveform

C (DC 
voltage)

0 V

Tracking servo
Sled servo
         OFF

Tracking servo
Sled servo
           ON

12. Press the 

[8]

 button on the remote control unit. (The tracking

servo and sledding servo are turned ON.) Confirm the C (DC
voltage) is almost equal to the A (DC voltage) is step 11.

13. Turn OFF the power, and remove the lead wire connected at

step 7.