MDS-B5 - Sony Audio Service Manual (repair manual). Page 14

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4-8. Focus Bias Adjustment
Adjusting Method :
1. Load a continuously recorded disc (Refer to “4-4. Creating MO
Continuously Recorded Disc”.).
2. Rotate the AMS knob and display “CPLAY MODE”.
3. Press the ENTER/YES button twice and display “CPLAY MID”.
4. Press the EDIT/NO button when “C1 = 
 AD = 
” is dis-
played.
5. Rotate the AMS knob and display “FBIAS ADJUST”.
6. Press the ENTER/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 fo-
cus bias value at which the C1 error rate becomes 220.
8. Press the ENTER/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 ENTER/YES button and display “ 
/
 c = 
”.
11. Check that the C1 error rate is below 50 and ADER is 00. Then
press the ENETR/YES button.
12. If the “(
)” in “
 - 
 - 
 (
)” is above 20, press the ENTER/
YES button.
If below 20, press the EDIT/NO button and repeat the adjust-
ment from step 2 again.
13. Press the EDIT/NO button and press the EJECT button to re-
move 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 us-
ing the average vale.
4-9. Error Rate Check
4-9-1. CD Error Rate Check
Checking Method :
1. Load a test disc TDYS-1.
2. Rotate the AMS knob and display “CPLAY MODE”.
3. Press the ENTER/YES button twice and display “CPLAY MID”.
4. “C1 = 
 AD = 
” is displayed.
5. Check that the C1 error rate is below 20.
6. Press the EDIT/NO button, stop playback, press the EJECT but-
ton, and remove the test disc.
4-9-2. MO Error Rate Check
Checking Method :
1. Load a continuously recorded disc (Refer to “4-4. Creating MO
Continuously Recorded Disc”.).
2. Rotate the AMS knob and display “CPLAY MODE”.
3. Press the ENTER/YES button twice and display “CPLAY MID”.
4. “C1 = 
 AD = 
” is displayed.
5. If the C1 error rate is below 50, check that ADER is 00.
6. Press the EDIT/NO button, stop playback, press the EJECT but-
ton, and remove the continuously recorded disc.
4-10. Focus Bias Check
Change the focus bias and check the focus tolerance amount.
Checking Method :
1. Load a continuously recorded disc (Refer to “4-4. Creating MO
Continuously Recorded Disc”.).
2. Rotate the AMS knob and display “CPLAY MODE”.
3. Press the ENTER/YES button twice and display “CPLAY MID”.
4. Press the EDIT/NO button when “C1 = 
 AD = 
” is dis-
played.
5. Rotate the AMS knob and display “FBIAS CHECK”.
6. Press the ENTER/YES button and display “ 
/
 c = 
”.
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 ENTER/YES button and display “ 
/
 b = 
”.
Check that the C1 error is not below 220 and ADER is not
above 00 every time.
8. Press the ENTER/YES button and display “ 
/
 a = 
”.
Check that the C1 error is not below 220 and ADER is not above
00 every time.
9. Press the EDIT/NO button, next press the EJECT button, and re-
move 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 prop-
erly. Adjust perform the beginning again.
C1 error
220
Focus bias value
(F. BIAS)
b
c
a
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