Sony MXD-D4 - Focus Bias Adjustment; Focus Bias Adjustment Procedure

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8. Turn the [ AMS ] (MD) knob so that the waveform
of the oscilloscope becomes the specified value.
(When the [ AMS ] (MD) knob is turned, the of
“EFB= ” changes and the waveform changes.) In this ad-
justment, waveform varies at intervals of approx. 2%. Adjust
the waveform so that the specified value is satisfied as much
as possible.
(Write power traverse adjustment)
Traverse Waveform
9. Press the [YES] button, and save the adjustment results in the
non-volatile memory. (“EFB = SAVE” will be displayed
for a moment)
10. “EFB = MO-P” will be displayed.
The optical pick-up moves to the pit area automatically and
servo is imposed.
11. Turn the [ AMS ] (MD) knob until the waveform of
the oscilloscope moves closer to the specified value.
In this adjustment, waveform varies at intervals of approx. 2%.
Adjust the waveform so that the specified value is satisfied as
much as possible.
Traverse Waveform
12. Press the [YES] button, and save the adjustment results in the
non-volatile memory. (“EFB = SAVE” will be displayed
for a moment.)
Next “EF MO ADJUST” (C07) is displayed. The disc stops
rotating automatically.
13. Press the [ EJECT] button and take out the disc.
14. Load the check disc (MD) TDYS-1.
15. Turn the [ AMS ] (MD) knob to display “EF CD
ADJUST” (C08).
16. Press the [YES] button to display “EFB = CD”. Servo is
imposed automatically.
17. Turn the [ AMS ] (MD) knob so that the waveform
of the oscilloscope moves closer to the specified value.
In this adjustment, waveform varies at intervals of approx. 2%.
Adjust the waveform so that the specified value is satisfied as
much as possible.
Traverse Waveform
18. Press the [YES] button, display “EFB = SAVE” for a mo-
ment and save the adjustment results in the non-volatile
memory.
Next “EF CD ADJUST” (C08) will be displayed.
19. Press the [ EJECT] button and take out the disc (MD) TDYS-
1.
Adjustment Location: BD (MD) board (see page 42)
13. FOCUS BIAS ADJUSTMENT
Adjusting Procedure:
1. Load the continuously-recorded disc. (Refer to “5. USING
THE CONTINUOUSLY RECORDED DISC”)
2. Turn the [ AMS ] (MD) knob to display “CPLAY2
MODE” (C36).
3. Press the [YES] button to display “CPLAY2MID”.
4. Press the [MENU/NO] button when “C = AD = ” is
displayed.
5. Turn the [ AMS ] (MD) knob to display “FBIAS
ADJUST” (C09).
6. Press the [YES] button to display “ / a = ”.
The first four digits indicate the C1 error rate, the two digits
after “/ ” indicate ADER, and the 2 digits after “a =” indicate
the focus bias value.
7. Turn the [ AMS ] (MD) knob clockwise and find the
focus bias value at which the C1 error rate becomes about 220
(refer to Note 2).
8. Press the [YES] button to display “ / b = ”.
9. Turn the [ AMS ] (MD) knob counterclockwise and
find the focus bias value at which the C1 error rate becomes
about 200.
10. Press the
[YES] button to display “ / c = ”.
11. Check that the C1 error rate is below 20 and ADER is 00.
Then press the [YES] button.
12. If the “( )” in “ - - ( )” is above 20, press the [YES]
button.
If below 20, press the [MENU/NO] button and repeat the ad-
justment from step 2.
13. Press the [ EJECT] button and take out the disc.
Note 1: The relation between the C1 error and focus bias is as shown in
the following figure. Find points A and B in the following figure
using the above adjustment. The focal point position C is auto-
matically calculated from points A and B.
Note 2: As the C1 error rate changes, perform the adjustment using the
average vale.
lL
lL
lL
lL
lL
A
lL
A
lL
lL
lL
A
A
B
VC
Specification A = B
A
B
VC
Specification A = B
A
B
VC
Specification A = B
C1 error
about
200
B
CA
Focus bias value