Sony MDS-JB920 Checks Prior to Parts Replacement and Adjustments, Forced Reset, Rec/Play

Page 8

Checks Prior to Parts Replacement and Adjustments

Before performing repairs, perform the following checks to determine the faulty locations up to a certain extent. Details of the procedures are described in “5 Electrical Adjustments”.

 

Criteria for Determination

Measure if unsatisfactory:

 

(Unsatisfactory if specified value is not satisfied)

 

 

 

 

 

Laser power check

• 0.9 mW power

• Clean the optical pick-up

(5-6-2 : See page 25)

Specified value : 0.84 to 0.92 mW

• Adjust again

 

• 7.0 mW power

• Replace the optical pick-up

 

Specified value : 6.8 to 7.2 mW

 

 

 

 

 

lop (at 7mW)

• Replace the optical pick-up

 

• Labeled on the optical pickup

 

 

Iop value ± 10mA

 

 

 

 

Traverse check

• Traverse waveform

• Replace the optical pick-up

(5-6-3 : See page 25)

Specified value : Below 10% offset

 

 

 

 

Focus bias check

• Error rate check

• Replace the optical pick-up

(5-6-4 : See page 26)

Specified value : For points a, b, and c

 

 

C1 error : Below 220

 

 

AD error : Below 2

 

 

 

 

C PLAY check

• Error rate check

• Replace the optical pick-up

(5-6-5 : See page 26)

Specified value:

 

 

a. When using test disc (MDW-74/AU-1)

 

 

C1 error : Below 80

 

 

AD error : Below 2

 

 

b. When using check disc (TDYS-1)

 

 

C1 error : Below 50

 

 

 

 

Self-recording/playback

• CPLAY error rate check

If always unsatisfactory:

check

Specified value:

• Replace the overwrite head

(REC/PLAY)

C1 error : Below 80

• Check for disconnection of the circuits around the

(5-6-6 : See page 26)

AD error : Below 2

overwrite head

 

 

 

 

 

If occasionally unsatisfactory:

 

 

• Check if the overwrite head is distorted

 

 

• Check the mechanism around the sled

 

 

 

TEMP check

• Unsatisfactory if displayed as T=@@ (##) [NG”

• Check for disconnection of the circuits around

(Temperature

NG

D101 (BD board)

compensation

(@@, ## are both arbitrary numbers)

• Check the signals around IC101, IC121, CN102,

offset check)

 

CN103 (BD board)

(5-6-1 : See page 25)

 

 

 

 

 

Note:

The criteria for determination above is intended merely to determine if satisfactory or not, and does not serve as the specified value for adjustments. When performing adjustments, use the specified values for adjustments.

Forced Reset

The system microprocessor can be reset in the following procedure.

Use these procedure when the unit cannot be operated normally due to the overrunning of the microprocessor, etc.

Procedure :

Disconnect the power plug, short-circuit jumper wire of JW705 and JW706 (RESET).

[BAT BOARD] (Component Side)

JW706

CN703

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Contents MDM-5A SpecificationsMDS-JE520 SELF-DIAGNOSIS Function GeneralItems of Error History Mode Items and Contents Section Servicing Notes Table of ContentsDiagrams Varoitus Flexible Circuit Board RepairingVarning JIG for Checking BD Board Waveform IOPRecord Precedure REC/PLAY Checks Prior to Parts Replacement and AdjustmentsForced Reset Retry Cause Display Mode PrecedureHexadecimal nBinary Conversion Table Front view Rear view Section GeneralLocation of Controls 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 GroupMID Operating the Continuous Playback ModeNon-Volatile Memory Mode EEP Mode 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 IC PIN Function Description Section DiagramsBD Board IC101 CXA2523AR RF AMP, FOCUS/TRACKING Error AMP 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 DigitalPlay Digital OUT Block Diagram Main Section∙ Signal Path Play Analog 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 RV760209 4-988-466-21 Spring ELECTROSTATIC, Leaf 206 201204 205 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
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