JVC-MXG78V-cs-sm 维修电路原理图.pdf

《JVC-MXG78V-cs-sm 维修电路原理图.pdf》由会员分享，可在线阅读，更多相关《JVC-MXG78V-cs-sm 维修电路原理图.pdf（65页珍藏版）》请在收音机爱好者资料库上搜索。

1、SERVICE MANUALCOMPACT COMPONENT SYSTEMNo.21026Sep. 2001COPYRIGHT 2001 VICTOR COMPANY OF JAPAN, LTD.MX-GT98V/MX-GT95VMX-GT88V/MX-GT85VMX-G78V/MX-G75VSafety precautionsImportant for laser productsPreventing static electricityDisassembly methodAdjustment method1-21-31-41-51-29Flow of functional operati

2、on until TOC readMaintenance of laser pickupReplacement of laser pickupDescription of major ICs 1-331-341-341-3549Contents(No MIC jack and MIC LEVEL volume for UN ver.)MX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75VCOMPACTDIGITAL VIDEOCOMPACTDIGITAL AUDIOArea suffixUS - SingaporeUN -AseanSP-MXGT9

3、8VSP-MXGT95VSP-MXGT98VSP-MXGT95VCA-MXGT98VCA-MXGT95VRadioFans.CN 收音机爱 好者资料库MX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-21. This design of this product contains special hardware and many circuits and components specially for safety purposes. For continued protection, no changes should be made

4、 to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services should be performed by qualified personnel only.2. Alterations of the design or circuitry of the product should not be made. Any design alter

5、ations of the product should not be made. Any design alterations or additions will void the manufacturers warranty and will further relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.3. Many electrical and mechanical parts in the products have specia

6、l safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristi

7、cs are identified in the Parts List of Service Manual. Electrical components having such features are identified by shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the same safety characteristics as the recommended

8、 replacement parts shown in the Parts List of Service Manual may create shock, fire, or other hazards.4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be separated from live parts, high temperature parts, moving parts and/or sharp edges for the

9、 prevention of electric shock and fire hazard. When service is required, the original lead routing and dress should be observed, and it should be confirmed that they have been returned to normal, after re-assembling.5. Leakage current check (Electrical shock hazard testing)After re-assembling the pr

10、oduct, always perform an isolation check on the exposed metal parts of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.Do not use a line isolation transformer during

11、this check.Plug the AC line cord directly into the AC outlet. Using a Leakage Current Tester, measure the leakage current from each exposed metal parts of the cabinet, particularly any exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage current must not

12、exceed 0.5mA AC (r.m.s.).Alternate check methodPlug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15 F AC-type capacitor between an exposed metal part and a kno

13、wn good earth ground.Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly any exposed metal part having a return path to the chassis, and measure the AC voltage across the resistor. Now, reverse the plug in the AC out

14、let and repeat each measurement. Voltage measured any must not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.). 1. This equipment has been designed and manufactured to meet international safety standards.2. It is the legal responsibility of the repairer to ensure that these safety

15、standards are maintained.3. Repairs must be made in accordance with the relevant safety standards.4. It is essential that safety critical components are replaced by approved parts.5. If mains voltage selector is provided, check setting for local voltage.Good earth groundPlace this probe on each expo

16、sedmetal part.AC VOLTMETER(Having 1000 ohms/volts,or more sensitivity)1500 10W0.15 F AC TYPE!Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system.In regard with component parts appearing on t

17、he silk-screen printed side (parts side) of the PWB diagrams, the parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the mark nearby are critical for safety. When replacing them, be sure to use the parts of the same type and rating as specified by

18、 the manufacturer. (Except the J&C version)RadioFans.CN 收音机爱 好者资料库MX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-3Important for laser products1.CLASS 1 LASER PRODUCT2.DANGER : Invisible laser radiation when open and inter lock failed or defeated. Avoid direct exposure to beam.3.CAUTION : There

19、are no serviceable parts inside theLaser Unit. Do not disassemble the Laser Unit. Replace the complete Laser Unit if it malfunctions.4.CAUTION : The compact disc player uses invisible laser radiation and is equipped with safety switches which prevent emission of radiation when the drawer is open and

20、 the safety interlocks have failed or are defeated. It is dangerous to defeat the safety switches.5.CAUTION : If safety switches malfunction, the laser is able to function.6.CAUTION : Use of controls, adjustments or performance of procedures other than those specified herein may result in hazardous

21、radiation exposure.VARNING : Osynlig laserstrlning r denna del r ppnad och sprren r urkopplad. Betrakta ej strlen.VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina nkymttmlle lasersteilylle.l katso steeseen.ADVARSEL : Usynlig laserstrling ved bning , nr sikkerhedsafbrydere er ude af funkt

22、ion. Undg udsttelse for strling.ADVARSEL : Usynlig laserstrling ved pning,nr sikkerhetsbryteren er avslott. unng utsettelse for strling.Position of labelsWARNING LABEL! CAUTIONPlease use enough caution not to see the beam directly or touch it in case of an adjustment or operationcheck.DANGER : Invis

23、ibie laser radiation when open and interlock or defeated.AVOID DIRECT EXPOSURE TO BEAM (e)VARNING : Osynlig laserstrlning r denna del r ppnad och sprren r urkopplad. Betrakta ej strlen. (s)VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina nkymttmlle lasersteilylle.l katso steeseen. (d)ADV

24、ARSEL :Usynlig laserstrling ved bning , nr sikkerhedsafbrydere er ude af funktion. Undg udsttelse for strling. (f)CLASS 1LASER PRODUCTCLASS 1LASER PRODUCTMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-4Preventing static electricity1. Grounding to prevent damage by static electricity Electrostat

25、ic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.2. About the earth processing for the destruction prevention by static electri

26、city In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity of the work environment.Be careful to use proper grounding in the area where repairs are being performed. 2-1 Ground the workbench Ground the workbench by laying conductive material

27、 (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it.2-2 Ground yourself Use an anti-static wrist strap to release any static electricity built up in your body. 3. Handling the optical pickup1. In order to maintain quality during transport an

28、d before installation, both sides of the laser diode on the replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.)2. Do not use a tester to check the condition of the laser diode in the optical pickup. The testers interna

29、l power source can easily destroy the laser diode. 4. Handling the traverse unit (optical pickup)1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit. 2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optica

30、l pickup. For specific details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a time when attaching it to the connector. 3. Handle the flexible cable carefully as it may break when subjected to strong forc

31、e. 4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn itConductive material (conductive sheet) or iron plate(caption)Anti-static wrist strapAttention when traverse unit is decomposed1. Remove the disk stopper and T. bracket on the CD changer mechanism a

32、ssembly. 2. Disconnect the harness from connector on the CD motor board.3. CD traverse unit is put up as shown in Fig.1. 4. Solder is put up before the card wire is removed from connector CN601 on the CD servo control board as shown in Fig. 2. (When the wire is removed without putting up solder, the

33、 CD pick-up assembly might destroy.) 5. Please remove solder after connecting the card wire with CN601 when you install picking up in the substrate.*Please refer to Disassembly method in the text for pick-up and how to detach the CD traverse mechanism. SolderingFig.1Fig.2CD changermechanism assembly

34、CD traverse unitFlexible cableMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-5Remove the six screws A on the back of the body.Remove the two screws B on both sides of the body.Remove the metal cover from the body by lifting the rear part of the cover.1.2.3.Disassembly methodRemoving the metal c

35、over (See Fig.1 to 3)Do not break the front panel tab fitted to the metal cover.CAUTION: Fig.1Fig.2Fig.3AAAMetal coverMetal coverBMetal coverBMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-6Prior to performing the following procedure, remove the metal cover.Disconnect the wire from connector CN

36、705 on the amplifier board.Remove the plastic rivet attaching the main board to the front assembly on the right side of the body.Disconnect the card wire from connector CN561 on the main board.Remove the two screws C on the upper side of the body and the two screws D on the back of the rear panel.Pu

37、ll both the rear panel and the front panel assembly to the outside, then remove the CD changer mechanism assembly by lifting the rear part of the assembly.1.2.3.4.5.Disconnect the card wire from connector CN504 on the inner side of the main board on the right side of the body. Remove the CD mechanis

38、m assembly.6.Removing the CD changer mechanism assembly (See Fig.4 and 6)Prior to performing the following procedure, remove the metal cover and the CD changer mechanism assembly.Turn over the CD changer mechanism assembly and remove the two screws E attaching the fan.1.Removing the fan (See Fig.7)T

39、o prevent damage to the CD fitting, be sure to pull both the rear panel and the front panel assembly enough to remove the CD changer mechanism assembly.CAUTION: At this point, one card wire on the underside of the CD mechanism assembly is still connected.REFERENCE: Fig.4Fig.5Fig.6Fig.7Front panel as

40、semblyCCCD changer mechanism assemblyRear panelMain boardCN561CN504CD changer mechanism assemblyDMain boardCN561Front panel assemblyRear panelCD changer mechanism assemblyFront panel assemblyAmplifier boardCN705CN504FanEECD changer mechanism assemblyRear panelPlastic rivetMX-GT98V/MX-GT95V/MX-GT88VM

41、X-GT85V/MX-G78V/MX-G75V1-7Prior to performing the following procedure, remove the metal cover and CD changer mechanism assembly.Disconnect the card wires from connector CN870, CN871 and CN315 on the main board respectively.Remove the wire clamp and disconnect the wire from connector CN703 on the amp

42、lifier board.Disconnect the wire from connector CN220 on the transformer board.Remove the two screws F on the bottom of the body.Release the two joints a on the lower right and left sides of the body using a screwdriver, and remove the front panel assembly toward the front.1.2.3.4.5.Removing the fro

43、nt panel assembly (See Fig.8 to 11)Fig.9Fig.10Fig.11F(Bottom)Joint aJoint aFront panel assemblyFront panel assemblyFig.8Wire clampAmplifier boardCN703Main boardCN870CN871CN315Transformer boardCN220Front panel assemblyMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-8Prior to performing the follow

44、ing procedure, remove the metal cover.Disconnect the card wire from connector CN1 on the tuner board on the right side of the body.Remove the plastic rivet fixing the tuner board.Remove the two screws G on the back of the body.1.2.3.Removing the tuner board (See Fig.12)Prior to performing the follow

45、ing procedure, remove the metal cover and the CD changer mechanism assembly.Remove the screw H attaching the rear cover on the back of the body.Push each tab of the four joints b in the direction of the arrow and release.Remove the fifteen screws G attaching the rear panel.Disengage the joints c on

46、each lower side of the rear panel using a screwdriver and remove the rear panel backward.1.2.3.4.Removing the rear cover / rear panel(See Fig.13 to 16)Fig.12Fig.13Fig.14Fig.15Fig.16CN1Plastic rivetTuner boardRear panelRear panelHGJoint bJoint bRear coverRear panelGGGGGJoint cJoint cRear panelRear pa

47、nelGMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-9Prior to performing the following procedure, remove the metal cover, the CD changer mechanism assembly, the rear panel and the antenna board.Disconnect the card wires from connector CN870, CN871 and CN315 on the main board.Disconnect the wires

48、 from connector CN704 and CN706 on the amplifier board.Remove the screw I attaching the main board on the right side ofthe body.Disconnect connector CN211 and CN212 on the main board from the regulator board.1.2.3.4.Removing the main board (See Fig.17 and 18)Prior to performing the following procedu

49、re, remove the metal cover, the CD changer mechanism assembly and the rear panel.Disconnect connector CN217 on the speaker board from the regulator board.1.Removing the speaker board (See Fig.19)It is not necessary to remove the main board.REFERENCE:Fig.17Fig.18Fig.19Front panel assemblyAmplifier bo

50、ardCN704CN706Main boardCN870CN871CN315Main boardFront panel assemblyICN211CN212Regulator boardRegulator boardCN217Speaker boardMX-GT98V/MX-GT95V/MX-GT88VMX-GT85V/MX-G78V/MX-G75V1-10Prior to performing the following procedure, remove the metal cover, the CD changer mechanism assembly and the rear pan