Sony MDS-JB920 Precautions for Checking Laser Diode Emissinon, Precautions for Adjustments

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2. PRECAUTIONS FOR CHECKING LASER DIODE EMISSINON

To check the emission of the laser diode during adjustments, never view directly from the top as this may lose your eye-sight.

3. PRECAUTIONS FOR USE OF OPTICAL PICK-UP (KMS-260A)

As the laser diode in the optical pick-up is easily damaged by static electricity, solder the laser tap of the flexible board when using it. Before disconnecting the connector, desolder first. Before con- necting the connector, be careful not to remove the solder. Also take adequate measures to prevent damage by static electricity. Handle the flexible board with care as it breaks easily.

pick-up

flexible board

 

laser tap

Optical pick-up flexible board

4. PRECAUTIONS FOR ADJUSTMENTS

1.When replacing the following parts, perform the adjustments and checks with  in the order shown in the following table.

 

Optical

 

 

BD Board

 

 

Pick-up

IC171

D101

 

IC101, IC121

IC192

 

 

 

 

 

 

 

1. Initial setting of

Â

Â

G

 

Â

G

adjustment value

 

 

 

 

 

 

 

 

2. Recording of IOP

 

 

 

 

 

 

information

Â

Â

G

 

G

G

(Value written in

 

the pick-up)

 

 

 

 

 

 

 

 

 

 

 

 

 

3. Temperature

 

 

 

 

 

 

compensation

G

Â

Â

 

G

G

offset adjustment

 

 

 

 

 

 

 

 

 

 

 

 

 

4. Laser power

Â

Â

G

 

Â

Â

adjustment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5. Traverse

Â

Â

G

 

Â

G

adjustment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6. Focus bias

Â

Â

G

 

Â

G

adjustment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7. Error rate check

Â

Â

G

 

Â

G

 

 

 

 

 

 

 

8. Auto gain output

Â

Â

G

 

Â

G

level adjustment

 

 

 

 

 

 

2.Set the test mode when performing adjustments. After completing the adjustments, exit the test mode. Perform the adjustments and checks in “group S” of the test mode.

3.Perform the adjustments to be needed in the order shown.

4.Use the following tools and measuring devices.

• Check Disc (MD) TDYS-1

(Parts No. 4-963-646-01)

TEST DISK (MDW-74/AU-1) (Parts No. 8-892-341-41)

Laser power meter LPM-8001 (Parts No. J-2501-046-A) or MD Laser power meter 8010S (Parts No. J-2501-145-A)

Oscilloscope (Measure after performing CAL of prove.)

Digital voltmeter

Thermometer

Jig for checking BD board waveform

(Parts No. : J-2501-149-A)

5.When observing several signals on the oscilloscope, etc., make sure that VC and ground do not connect inside the oscil- loscope.

(VC and ground will become short-circuited.)

6.Using the above jig enables the waveform to be checked with- out the need to solder.

(Refer to Servicing Notes on page 6.)

7.As the disc used will affect the adjustment results, make sure that no dusts nor fingerprints are attached to it.

Laser power meter

When performing laser power checks and adjustment (electrical adjustment), use of the new MD laser power meter 8010S (J-2501- 145-A) instead of the conventional laser power meter is conve- nient.

It sharply reduces the time and trouble to set the laser power meter sensor onto the objective lens of the pick-up.

5.CREATING CONTINUOUSLY RECORDED DISC

* This disc is used in focus bias adjustment and error rate check. The following describes how to create a continuous recording disc.

1.Insert a disc (blank disc) commercially available.

2.Rotate the [ÊÊÊÊÊÊÊÊAMSÊÊÊÊÊÊÊÊ]- ± knob and display “CREC MODE”. (C31)

3.Press the [YES] button again to display “CREC MID”. Display “CREC (0300)” and start to recording.

4.Complete recording within 5 minutes.

5.Press the [MENU/NO] button and stop recording .

6.Press the [ÊÊÊÊÊEJECT]¤ button and remove the disc.

The above has been how to create a continuous recorded data for the focus bias adjustment and error rate check.

Note :

• Be careful not to apply vibration during continuous recording.

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Contents Specifications MDS-JE520MDM-5A SELF-DIAGNOSIS Function GeneralItems of Error History Mode Items and Contents Table of Contents DiagramsSection Servicing Notes Flexible Circuit Board Repairing VarningVaroitus JIG for Checking BD Board Waveform IOPRecord Precedure Checks Prior to Parts Replacement and Adjustments Forced ResetREC/PLAY Retry Cause Display Mode PrecedureHexadecimal nBinary Conversion Table Section General Location of ControlsFront view Rear view Page Page Section Disassembly CaseFront Panel Seciton Main BoardMechanism Section MDM-5A Slider CAMBase Unit MBU-5A, BD Board SW BOARD, Loading Motor M103Section Test Mode Precautions for USE of Test ModeSetting the Test Mode Exiting the Test ModeSelecting the Test Mode Display Contents Mark GroupOperating the Continuous Playback Mode Non-Volatile Memory Mode EEP ModeMID Test Mode Displays Functions of Other ButtonsAuto gain display Not used in servicing Detrack check display Not used in servicingDisplay Contents When Lit When Off Meanings of Other DisplaysSection Electrical Adjustments Parts Replacement and AdjustmentPrecautions for Checking Laser Diode Emissinon Precautions for USE of Optical PICK-UP KMS-260APrecautions for Adjustments Laser power meterTemperature Compensation Offset Check Laser Power CheckCheck Prior to Repairs Traverse CheckPlay Checking MO Error Rate Check CD Error Rate CheckFocus Bias Check Self-Recording/playback CheckInitial Setting of Adjustment Value Temperature Compensation Offset AdjutmentLaser Power Adjustment Recording and Displaying the IOP InformationTraverse Adjustment Focus Bias Adjustment Error Rate Check Auto Gain Control Output Level AdjustmentCD Auto Gain Control Output Level Adjustment MO Auto Gain Control Output Level AdjustmentAdjusting Points and Connecting Points Section Diagrams BD Board IC101 CXA2523AR RF AMP, FOCUS/TRACKING Error AMPIC PIN Function Description Srdt SensXrst SqsyXras XWEMvci AsyoSrdr SfdrSprd SpfdMain Board IC100 CXD8607N A/D Converter Avddl VDD1TEST2 LvddMain Board IC800 M30610MCA-264FP System Controller MDS-JB920 Block Diagram Servo Section ∙ Signal PathREC Analog REC DigitalBlock Diagram Main Section ∙ Signal Path Play Analog OUTPlay Digital OUT Circuit Boards Location Printed Wiring Boards BD Section MDS-JB920 Schematic Diagram BD /2 See 53 for Waveforms. See page 70 and 71 for IC Block DiagramsWaveforms BD board Main board Disp board MDS-JB920 MDS-JB920 MDS-JB920 MDS-JB920 Other layers pattern Side a US, CND Schematic Diagram Panel Section See page 54 for Waveforms Schematic Diagram BD Switch Section Printed Wiring Board BD Switch SectionIC Block Diagrams BD Board IC101 CXA2523ARIC121 CXD2654R IC152 BH6511FS-E2Main Board IC100 CXD8607N IC101 CXA8054MIC203 CXA8042ASIC200 CXD8767N SN74HC153ANS SN74HCU04ANS-E20Section Exploded Views Chassis SectionFront Panel Section Supplied with RV760206 201 204 205209 4-988-466-21 Spring ELECTROSTATIC, Leaf Base Unit Section MBU-5A Section Electrical Parts List TANTAL. Chip DiodeDiode F1J6TP CXA2523ARDisp Main C252 Mylar HZS6C1L HZ7.5CP-TKCXA8042AS SN74HC153ANS390 Main PSW Coil with Core VibratorLED SEL6210S-TH10 Standby LED SEL6810A-TH10 Mega Control TransistorSW VOL Sony Corporation