DHC-MD7, MDS-M9 - Sony Audio Service Manual (repair manual). Page 16

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11. Rotate the SELECTOR knob until the waveform of the

oscilloscope moves closer to the specified value.
In this adjustment, waveform varies at intervals of approx. 3%.
Adjust the waveform so that the specified value is satisfied as
much as possible.

(Traverse Waveform)

Adjusting method :
1. Connect an oscilloscope to TP (TEO) and TP (VC) of the BD

board.

2. Load a MO disc (any available on the market).
3. Press the 

0 button or ) button and move the optical pick-up

outside the pit.

4. Rotate the SELECTOR knob and display “EFBAL ADJUST”.
5. Press the YES button and display “EFBAL MO-W”.

(Laser power WRITE power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)

6. Adjust RV101 of the BD board so that the waveform of the

oscilloscope becomes the specified value.
(MO groove write power traverse adjustment)

(Traverse Waveform)

7. Press the YES button and display “EFB = $   MO-R”.

(Laser power : MO reading)

8. Rotate the SELECTOR knob so that the waveform of the

oscilloscope becomes the specified value.
(When the SELECTOR knob is rotated, the    of “EFB-  ” changes
and the waveform changes.) In this adjustment, waveform varies
at intervals of approx. 3%. Adjust the waveform so that the
specified value is satisfied as much as possible.
(MO groove read power traverse adjustment)

(Traverse Waveform)

12. Press the YES button, display “EFB =   SAVE” for a moment

and save the adjustment results in the non-volatile memory.
Next “EFBAL CD” is displayed. The disc stops rotating
automatically.

13. Press the EJECT button and remove the MO disc.
14. Load the test disc TDYS-1.
15. Press the YES button and display “EFB =   CD”. Servo is im-

posed automatically.

16. Rotate the SELECTOR knob so that the waveform of the

oscilloscope moves closer to the specified value.
In this adjustment, waveform varies at intervals of approx. 3%.
Adjust the waveform so that the specified value is satisfied as
much as possible.

(Traverse Waveform)

17. Press the YES button, display “EFB = $   SAVE” for a moment

and save the adjustment results in the non-volatile memory.
Next “EFBAL ADJUST” is displayed.

18. Press the EJECT button and remove the test disc TDYS-1.

Note 1 : Data will be erased during MO reading if a recorded disc is

used in this adjustment.

Note 2 : If the traverse waveform is not clear, connect the

oscilloscope as shown in the following figure so that it can
be seen more clearly.

Oscilloscope

BD board
TP (TEO)
TP (VC)

VC

A

B

Specification A = B

VC

A

B

Specification A = B

9. Press the YES button, display “EFB = $   SAVE” for a moment

and save the adjustment results in the non-volatile memory.
Next “EFBAL MO-P” is displayed.

10. Press the YES button and display “EFB = $   MO-P”.

The optical pickup moves to the pit area automatically and servo
is imposed.

VC

A

B

Specification A = B

VC

A

B

Specification A = B

Oscilloscope

330 k

Ω

10pF

TP (TEO)

TP (VC)