Sony MDS-JE770 specifications Focus Bias Adjustment

Page 33

11.Rotate the lAMS L 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)

A

VC

B

Specification A = B

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 ADJUS” (C07) is displayed. The disc stops ro- tating automatically.

13.Press the AEJECT button and remove the disc.

14.Load the check disc (MD) TDYS-1.

15.Roteto lAMS L knob and display “EF CD ADJUS” (C08).

16. Press the YES button and display “EFB = CD”. Servo is imposed automatically.

17.Rotate the lAMS L 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)

A

VC

B

Specification A = B

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 ADJUS”(C08) will be displayed.

19.Press the AEJECT button and remove the check disc (MD) TDYS-1.

Note 1 : MO reading data will be erased during if a recorded disc is used in this adjustment.

Note 2 : If the traverse waveform is not clear, connect the oscillo- scope as shown in the following figure so that it can be seen more clearly.

Oscilloscope

BD board

330 kΩ

CN105 pin 4 (TE)

10pF

CN105 pin 6

(VC)

 

MDS-JE770

5-13. FOCUS BIAS ADJUSTMENT

Adjusting Procedure :

1.Load a test disk (MDW-74/GA-1).

2.Rotate the l AMS L knob and display “CPLAY1 MODE”(C34).

3.Press the YES button and display “CPLAY1 MID”.

4. Press the

MENU/NO

button when “C =

AD = ” is

displayed.

 

5.Rotate the l AMS L knob and display “FBIAS ADJUS”(C09).

6.Press the YES button and display “ / a = ”.

The first four digits indicate the C error rate, the two digits after

[/]indicate ADER, and the 2 digits after [a =] indicate the focus bias value.

7.Rotate the lAMS L knob in the clockwise direction and find the focus bias value at which the C error rate becomes 220 (Refer to Note 2).

8.Press the YES button and display “ / b = ”.

9.Rotate the lAMS L knob in the counterclockwise di- rection and find the focus bias value at which the C error rate becomes 220.

10.Press the YES button and display “ / c = ”.

11.Check that the C 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

 

adjustment from step 2.

 

 

 

 

13.

Press the

AEJECT

button to remove the test disc.

Note 1 : The relation between the C 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 C error rate changes, perform the adjustment using the average vale.

Cerror

220

b

c

a

Focus bias value

 

 

 

(F. BIAS)

33

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Contents 873-890-11 SpecificationsMDS-S50 MDM-7ASupplied accessories Genera l Power requirementsMDS-JE770 SELF-DIAGNOSIS FunctionItems of Error History Mode Items and Contents Disassembly Table of ContentsDiagrams Exploded ViewsFlexible Circuit Board Repairing MDS-JE770 Section Service NotesIOP JIG for Checking BD Board WaveformRecord Precedure Optical PICK-UP Block Type Discrimination KSN-260EChecks Prior to Parts Replacement and Adjustments Forced ResetMain Board Component Side Bit Binary Retry Cause Display ModeBit When Binary Higher Bits Lower Bits Hexa DetailsHexadecimal Binary Button Descriptions MDS-JE770 Section GeneralDisassembly Flow MDS-JE770 Section DisassemblyFront Panel Section Two screws Main BoardOver Light Head HR901, BD Board Mechanism Deck Section MDM-7ALoading Motor Assy M103 Holder AssyOptical PICK-UP Sled Motor Assy M102, SliderSpindle Moter Assy M101 Precautions for USE of Test Mode MDS-JE770 Section Test ModeSetting the Test Mode Exiting the Test ModeSelecting the Test Mode MENU/NO Operating the Continuous Playback ModeMode display Test Mode DisplaysError rate display Functions of Other ButtonsMeanings of Other Displays When Memory NG is DisplayedAutomatic SELF-DIAGNOSIS Function InformationMDS-JE770 Section Electrical Adjustments Parts Replacement and AdjustmentCheck before replacement Auto Gain Control Output Level Adjustment flowPrecautions for USE of Optical PICK- UP KMS-260B/260E Precautions for Checking Laser Diode EmissionPrecautions for Adjustments Temp AdjustChecks Prior to Repairs Using the Continuously Recorded DiscOther Checks Auto CheckTraverse Check Traverse WaveformCD Error Rate Check Play Check MO Error Rate CheckFocus Bias Check Self-Recording/playback CheckInitial Setting of Adjustment Value Temperature Compensation Offset AdjutmentLaser Power Adjustment Iop NV Save Traverse AdjustmentFocus Bias Adjustment Auto Gain Control Output Level Adjustment Error Rate CheckCD Auto Gain Control Output Level Adjustment MO Auto Gain Control Output Level AdjustmentAdjusting Points and Connecting Points Circuit Boards Location MDS-JE770 Section DiagramsFor printed wiring boards For schematic diagramsBD Board Main BoardBlock Diagrams BD Section IC171IC190 Main Section IC360 2/2IC1 2/2 Semiconductor SemiconductorOVEROptical Pick UP Block Write HeadBoard Board Main Main Schematic Diagram Main /2 See page 51 for IC Block Diagrams IC1 Model is printed on diagramKB Board Display BoardKEY-SW Board HP BoardLED Drive Schematic Diagram Display SectionC951 C952 RY910D910 CN921 C924 LF900 C910Main Schematic Diagram Power SectionIC101 CXA2523AR BD Board IC Block DiagramsIC500 AK4524 Main Board IC PIN Function Description IC101 CXA2523AR RF Amplifier BD BoardPin No Pin Name Description Pin No Pin Name Desription Asyo MvciAsyi AvddFfdr TfdrFrdr FS4ADA.RESET IIC PowerFldt FlckEPN ADA. LatchDINT1/H Clip ProtectSTB TimerBeep SW REC FlcsVDISP1 ResetVFL1 OSC0Chassis Section Section Exploded ViewsNot supplied Supplied with J790 FL750 With RV790 FL750 1-517-987-11 Indicator TUBE, FluorescentMechanism MDM-7A Motor ASSY, Spindle HEAD, Over LightMotor ASSY, Sled Motor ASSY, LoadingMDS-JE770 Section Electrical Parts List Metal Chip SwitchJumper Resistor ShortMDS-JE770 Display HP KB KEY-SW KEY-SW Main MDS-JE770 Main 2SD2144S-TP-UVW Resistor VOL-SEL MDS-JE770 Main PTMemo MDS-JE770 Revision History
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