Sony MDS-JB930 Service Manual page 25

[YES]
9. Press the button to display "EFB =
Then, the optical pick-up moves to the pit area automatically
and servo is imposed.
10. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not turn the
knob.
Traverse Waveform
VC
Specified value : Below 10% offset value
Offset value (%) =
[YES]
11. Press the button to display "EF MO CHECK"
The disc stops rotating automatically.
[EJECT ]
12. Press the § button and take out the disc.
13. Load the check disc (MD) TDYS-1.
[ AMS ]
±
14. Turn the ≠
(C04).
[YES]
15. Press the button to display "EFB =
imposed automatically.
16. Observe the waveform of the oscilloscope, and check that the
specified value is satisfied. Do not turn the
knob.
Traverse Waveform
VC
Specified value : Below 10% offset value
Offset value (%) =
[YES]
17. Press the button to display "EF CD CHECK".
[EJECT ]
18. Press the § button and take out the check disc.
MO-P".
[ AMS ]
≠
A
B
I A – B I
X 100
2 (A + B)
knob and display "EF CD CHECK"
CD". Servo is
[ AMS ]
≠
A
B
I A – B I
X 100
2 (A + B)
6-4. Focus Bias Check
Change the focus bias and check the focus tolerance amount.
Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
[ AMS ]
± 2. Turn the ≠
(C30).
[YES]
3. Press the
[MENU/NO]
4. Press the
displayed.
[ AMS ]
5. Turn the ≠
(C05).
[YES]
6. Press the
The first four digits indicate the C1 error rate, the two digits
after [/] indicate ADER, and the 2 digits after [c =] indicate
the focus bias value.
Check that the C1 error is below 50 and ADER is below 2.
[YES]
7. Press the
Check that the C1 error is about 200 and ADER is below 2.
[YES]
8. Press the
Check that the C1 error is about 200 and ADER is below 2.
[MENU/NO]
9. Press the
ton and take out the test disc.
6-5. C PLAY Checking
MO Error Rate Check
±
Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
[ AMS ]
2. Turn the ≠
(C30).
[YES]
3. Press the
4. The display changes to "C =
5. If the C1 error rate is below 80, check that ADER is below 2.
[MENU/NO]
6. Press the
[EJECT ]
§ button and take out the test disc.
CD Error Rate Check
Checking Procedure :
1. Load the check disc (MD) TDYS-1.
[ AMS ]
2. Turn the ≠
(C30).
[YES]
3. Press the
4. The display changes to "C =
5. Check that the C1 error rate is below 50.
[MENU/NO]
6. Press the
[EJECT ]
§ button and take out the check disc.
6-6. Self-Recording/playback Check
Prepare a continuous recording disc using the unit to be repaired
and check the error rate.
Checking Procedure :
1. Load a recordable disc (blank disc).
[ AMS ]
2. Turn the ≠
(C31).
[YES]
3. Press the
4. When recording starts, lights up "
@@@@" (@@@@ is the address).
5. About 1 minute later, press the
continuous recording.
[ AMS ]
6. Turn the
≠
(C30).
[YES]
7. Press the
8. "C = AD =
9. Check that the C1 error becomes below 80 and the AD error
below 2.
[MENU/NO]
10. Press the
[EJECT ]
§
button and take out the disc.
± knob to display "CPLAY MODE"
button twice to display "CPLAY MID".
button when "C =
± knob to display "FBIAS CHECK"
button to display " / c =
button to display " / b =
button to display " / a =
[EJECT ]
button, then press the
± knob to display "CPLAY MODE"
button to display "CPLAY MID".
AD = ".
button to stop playback, then press the
± knob to display "CPLAY MODE"
button twice to display "CPLAY MID".
AD = ".
button to stop playback, then press the
± knob to display "CREC MODE"
button to display "CREC MID".
REC
" and display "CREC
[MENU/NO]
± knob to display "CPLAY MODE"
button to display "CPLAY MID".
" will be displayed.
button to stop playback, then press the
AD = " is
".
".
".
§
but-
button to stop
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