SONY MDSB6P
Service Manual

4-7. Focus Bias Adjustment
Adjusting Method : 1. Load a continuously recorded disc (MDW-74/AU-1). 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 displayed. 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 focus 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 adjustment from step 2 again. 13. Press the EDIT/NO button and press the EJECT 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 vale.
C1 error

4-8. Error Rate Check
4-8-1. 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 button, and remove the test disc. 4-8-2. MO Error Rate Check Checking Method : 1. Load a continuously recorded disc (MDW-74/AU-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. If the C1 error rate is below 50, check that ADER is 00. 6. Press the EDIT/NO button, stop playback, press the EJECT button, and remove the continuously recorded disc.

4-9. Focus Bias Check
Change the focus bias and check the focus tolerance amount. Checking Method : 1. Load a continuously recorded disc (MDW-74/AU-1). 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 displayed. 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 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.

220

Focus bias value (F. BIAS) b c a

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