Sony MDS-JA30ES Service Manual page 17

Focus Bias Adjustment
Adjusting Method :
1. Load a continuously recorded disc (Refer to "Page 14 Creating
Continuously Recorded Disc".).
2. Rotate the AMS knob and display "CPLAY MODE".
3. Press the YES button twice and display "CPLAY MID".
4. Press the NO button when "C = AD = " is displayed.
5. Rotate the AMS knob and display "FBIAS ADJUS".
6. Press the YES button and 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. Rotate the AMS knob in the clockwise direction and find the
focus bias value at which the C1 error rate becomes 220.
8. Press the YES button and display " / b =
9. Rotate the AMS knob in the counterclockwise direction and
find the focus bias value at which the C1 error rate becomes
220.
10. Press the YES button and display " / c =
11. Check that the C1 error rate is below 50 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 NO button and repeat the adjustment
from step 2 again.
13. Press the NO button and press the § OPEN/CLOSE button to
remove the continuously recorded 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 automatically calculated from points a
and b.
Note 2 : As the C1 error rate changes, perform the adjustment using
the average value.
C1 error
220
Focus bias v a lue
(F. BIAS)
b c a
Error Rate Check
CD Error Rate Check
Checking Method :
1. Load a check disc TGYS-1.
2. Rotate the AMS knob and display "CPLAY MODE".
3. Press the YES button twice and display "CPLAY MID".
4. "C = AD = " is displayed.
5. Check that the C1 error rate is below 20.
". 6. Press the NO button, stop playback, press the § OPEN/CLOSE
button, and remove the test disc.
MO Error Rate Check
Checking Method :
". 1. Load a continuously recorded disc (Refer to "Page 14 Creating
Continuously Recorded Disc".).
2. Rotate the AMS knob and display "CPLAY MODE".
3. Press the YES button twice and display "CPLAY MID".
". 4. "C = AD = " is displayed.
5. If the C1 error rate is below 50, check that ADER is 00.
6. Press the NO button, stop playback, press the § OPEN/CLOSE
button, and remove the continuously recorded disc.
Focus Bias Check
Change the focus bias and check the focus tolerance amount.
Checking Method :
1. Load a continuously recorded disc (Refer to "Page 14 Creating
Continuously Recorded Disc".).
2. Rotate the AMS knob and display "CPLAY MODE".
3. Press the YES button twice and display "CPLAY MID".
4. Press the NO button when "C = AD =
5. Rotate the AMS knob and display "FBIAS CHECK".
6. Press the YES button and display "
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 00.
7. Press the YES button and display "
Check that the C1 error is not below 220 and ADER is not
above 00 every time.
8. Press the YES button and display "
Check that the C1 error is not below 220 and ADER is not
above 00 every time.
Press the NO button, next press the § OPEN/CLOSE button,
9.
and remove the continuously recorded disc.
Note 1 : If the C1 error and ADER are above 00 at points a or b,
the focus bias adjustment may not have been carried out
properly. Adjust perform the beginning again.
— 17 —
Adjusting Points and Connecting Points
[BD BOARD] (SIDE A)
" is displayed.
/ c = ".
[BD BOARD] (SIDE B)
/ b = ".
(IOP)
/ a = ".
RV101
IC171
D101
IC191
(I + 5V)
IC101
(VC)
RV102
(TEO)
IC121
— 18 —
MDS-JA30ES