Jvc-THA-75-Service-Manual电路原理图.pdf

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1、SERVICE MANUALCOPYRIGHT 2003 VICTOR COMPANY OF JAPAN, LTD.No.220092003/02TH-A75DVD DIGITAL CINEMA SYSTEM2200900302TH-A75TABLE OF CONTENTS1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22 Disassemb

2、ly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-53 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3、 . . 1-154 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16STANDBYCOMPACTSUPER VIDEO DIGITALEXPRO LOGICPROGRESSIVEPHONESSOURCE VOLUME RMSTHA75UDVD CINEMA SYSTEMCHANNEL/ZOOM VOLUMETV VOLTUNINGSTO

4、PDIMMERPAUSEFF/REWTV/VIDEO MUTINGRECPLAYDOWN UPMEMORY STROBEDVD VCR 1AUDIOVCR/DBSANGLEFM/AMSUBTITLE DECODERETURN DIGESTVFPTOP MENU MENUCONTROL EFFECTS.WFR TESTSLEEPTVVCRSETTINGTV RETURNENTERONSCREENCHOICEFM MODE12345678910 0 +10100+TV AUDIOVCRSOUNDAUDIO/TV/VCRCATV/DBSPROGRESSIVESURROUND OFFDSPCENTER

5、+SURR-L SURR-RS-BACK+ADJUSTO.T.REPLAYXV-THA75SP-XSA75SP-WA75SP-XCA75Area SuffixUS - SingaporeUP - KoreaUT - TaiwanUX - Saudi ArabiaTH-A751-2 (No.22009)SECTION 1Important Safety Precautions1.1 Safety Precautions(1) This design of this product contains special hardware andmany circuits and components

6、specially for safety purposes.For continued protection, no changes should be made to theoriginal design unless authorized in writing by the man-ufacturer. Replacement parts must be identical to thoseused in the original circuits. Services should be per-formed by qualified personnel only.(2) Alterati

7、ons of the design or circuitry of the product shouldnot be made. Any design alterations of the product shouldnot be made. Any design alterations or additions will voidthe manufacturers warranty and will further relieve themanufacture of responsibility for personal injury or propertydamage resulting

8、therefrom.(3) Many electrical and mechanical parts in the products havespecial safety-related characteristics. These characteris-tics are often not evident from visual inspection nor can theprotection afforded by them necessarily be obtained by us-ing replacement components rated for higher voltage,

9、 watt-age, etc. Replacement parts which have these special safetycharacteristics are identified in the Parts List of Service Manu-al. Electrical components having such features are iden-tified by shading on the schematics and by ( ) on theParts List in the Service Manual. The use of a substitute re-

10、placement which does not have the same safety character-istics as the recommended replacement parts shown in theParts List of Service Manual may create shock, fire, or oth-er hazards.(4) The leads in the products are routed and dressed with ties,clamps, tubings, barriers and the like to be separated

11、 fromlive parts, high temperature parts, moving parts and/orsharp edges for the prevention of electric shock and firehazard. When service is required, the original lead routingand dress should be observed, and it should be confirmedthat they have been returned to normal, after reassembling.(5) Leaka

12、ge shock hazard testing)After reassembling the product, always perform an isolationcheck on the exposed metal parts of the product (antennaterminals, knobs, metal cabinet, screw heads, headphonejack, control shafts, etc.) to be sure the product is safe tooperate without danger of electrical shock.Do

13、 not use a line isolation transformer during this check. Plug the AC line cord directly into the AC outlet. Using a“Leakage Current Tester“, measure the leakage currentfrom each exposed metal parts of the cabinet, particular-ly any exposed metal part having a return path to thechassis, to a known go

14、od earth ground. Any leakage cur-rent must not exceed 0.5mA AC (r.m.s.). Alternate check methodPlug the AC line cord directly into the AC outlet. Use an ACvoltmeter having, 1,000 ohms per volt or more sensitivity inthe following manner. Connect a 1,500 ohm 10W resistorparalleled by a 0.15 F AC-type

15、capacitor between anexposed metal part and a known good earth ground.Measure the AC voltage across the resistor with the ACvoltmeter. Move the resistor connection to each exposed metal part,particularly any exposed metal part having a return path tothe chassis, and measure the AC voltage across the

16、resistor.Now, reverse the plug in the AC outlet and repeat eachmeasurement. Voltage measured any must not exceed 0.75V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.). 1.2 Warning(1) This equipment has been designed and manufactured tomeet international safety standards.(2) It is the legal respo

17、nsibility of the repairer to ensure thatthese safety standards are maintained.(3) Repairs must be made in accordance with the relevantsafety standards.(4) It is essential that safety critical components are replacedby approved parts.(5) If mains voltage selector is provided, check setting for localv

18、oltage.1.3 CautionBurrs formed during molding may be left over on some partsof the chassis. Therefore, pay attention to such burrs in the case of pre-forming repair of this system.1.4 Critical parts for safetyIn regard with component parts appearing on the silk-screenprinted side (parts side) of the

19、 PWB diagrams, the parts that areprinted over with black such as the resistor ( ), diode ( )and ICP ( ) or identified by the “ “ mark nearby are criticalfor safety. When replacing them, be sure to use the parts of the same typeand rating as specified by the manufacturer. (Except the JC version)TH-A7

20、5(No.22009)1-31.5 Preventing static electricityElectrostatic 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.1.5.1 Grounding to p

21、revent damage by static electricityStatic electricity in the work area can destroy the optical pickup (laser diode) in devices such as DVD players. Be careful to use proper grounding in the area where repairs are being performed. (1) Ground the workbenchGround the workbench by laying conductive mate

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

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

24、power source can easilydestroy the laser diode. 1.6 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

25、l pickup. For specific details, refer to the replace-ment procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a timewhen attaching it to the connector. (3) Handle the flexible cable carefully as it may break when subjected to strong for

26、ce. (4) I t is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.1.7 Attention when traverse unit is decomposed*Please refer to “Disassembly method“ in the text for the DVD pickup unit. Apply solder to the short land sections before the flexible wire is disc

27、onnected from the connector CN101 on the DVD servo board. (If the flexible wire is disconnected without applying solder, the DVD pickup may be destroyed by static electricity.) In the assembly, be sure to remove solder from the short land sections after connecting the flexible wire.DVD mechanism ass

28、emblyCN101DVD servo boardShort land sectionsFlexible wireTH-A751-4 (No.22009)1.8 Important for laser products (1) CLASS 1 LASER PRODUCT(2) DANGER : Invisible laser radiation when open and interlock failed or defeated. Avoid direct exposure to beam.(3) CAUTION : There are no serviceable parts inside

29、the Laser Unit. Do not disassemble the Laser Unit. Replace thecomplete Laser Unit if it malfunctions.(4) CAUTION : The compact disc player uses invisible laserradiation and is equipped with safety switches which prevent emission of radiation when the drawer is open andthe safety interlocks have fail

30、ed or are de feated. It is dangerous to defeat the safety switches.(5) CAUTION : If safety switches malfunction, the laser is ableto function.(6) CAUTION : Use of controls, adjustments or performance ofprocedures other than those specified herein may result inhazardous radiation exposure.CAUTIONPlea

31、se use enough caution not to see the beam directlyor touch it in case of anadjustment or operation check.VARNINGOsynlig laserstrlning r denna del r ppnad och sprren rurkopplad. Betrakta ej strlen.VAROAvattaessa ja suojalukitus ohitettaessa olet alttiina nkymt-tmlle lasersteilylle. l katso steeseen.A

32、DVARSELUsynlig laserstrling ved bning, nr sikkerhedsafbrydere erude af funktion. Undg udsasttelse for strling.ADVARSELUsynlig laserstrling ved pning, nr sikkerhetsbryteren er avs-lott. unng utsettelse for strling.REPRODUCTION AND POSITION OF LABELSWARNING LABELCLASS 1LASER PRODUCTTH-A75(No.22009)1-5

33、SECTION 2Disassembly method2.1 Main body section2.1.1 Removing the top cover (See Figs.1 to 4.)(1) From the right and left sides of the main body, remove thefour screws A attaching the top cover. (See Figs.1 and 2.)(2) From the back side of the main body, remove the twoscrews B attaching the top cov

34、er. (See Fig.3.)(3) Lift the rear section of the top cover, slide the top coverslightly in the direction of the arrow. (See Fig.4.)(4) Disengage the engagement sections a of the top coverfrom the main body. (See Fig.4.)Fig.1Fig.2Fig.3Fig.4Top coverATop coverARear panelTop coverBTop coveraTH-A751-6 (

35、No.22009)2.1.2 Removing the front panel assembly (See Figs.5 to 8.) Remove the top cover.(1) From the left side of the main body, push the section b ofthe slide cam using the screw driver, etc. (See Fig.5.)(2) Pull out the tray. (See Fig.5.)(3) Push the tray fitting assembly of the tray in the direc

36、tion ofthe arrow and then remove the tray fitting assembly. (SeeFig.6.)(4) Return the tray into the DVD mechanism assembly.(5) From the bottom side of the main body, remove the fourscrews C attaching the front panel assembly. (See Fig.7.)(6) From the top side of the main body, remove the two screwsD

37、 attaching the front panel assembly. (See Fig.8.)(7) Disconnect the card wires from the connectors CN206 andCN207 on the main board. (See Fig.8.)(8) Remove the screw E attaching the lug wire. (See Fig.8.)(9) While opening the hooks c to the right and left sides of thefront panel assembly in the dire

38、ction of the arrow 1, removethe front panel assembly in the direction of the arrow 2.(See Fig.8.)Reference:In the assembly, through the card wire in the barrier andthen hold the card wire to the sections d of the barrier.(See Fig.8.)Fig.5Fig.6Fig.7Fig.8Slide camFront panel assemblybTrayTrayTray fitt

39、ing assemblyFront panel assemblyFront panel assemblyChassis baseCMain boardFront panel assemblyLug wireHook cBarrierCN20721CN206dD EHook c1TH-A75(No.22009)1-72.1.3 Removing the DVD mechanism assembly (See Fig.9.) Remove the top cover. Remove the front panel assembly.(1) From the top side of the main

40、 body, remove the barrier.(2) Disconnect the card wires from the connectors CN208 andCN209 on the main board.(3) Remove the three screws F attaching the DVD mechanismassembly.(4) Take out the DVD mechanism assembly from the chassisbase.Fig.92.1.4 Removing the DSP board (See Figs.10 and 11.) Remove t

41、he top cover.(1) From the top side of the main body, disconnect the cardwires from the connectors CN591 and CN592 on the DSPboard. (See Fig.10.)(2) From the back side of the main body, remove the threescrews G attaching the DSP board. (See Fig.11.)(3) Remove the DSP board from the section e of the b

42、arrier,take out the DSP board. (See Fig.10.)Reference:When attaching the DSP board, hang the DSP board tothe section e of the barrier. (See Fig.10.)2.1.5 Removing the tuner (See Figs.10 and 11.) Remove the top cover.(1) From the top side of the main body, disconnect the cardwire from the connector C

43、N1 on the tuner. (See Fig.10.)(2) From the back side of the main body, remove the twoscrews H attaching the tuner. (See Fig.11.)Fig.10Fig.11Main boardCN209 CN208FFCard wireCard wireBarrierChassis baseDVDmechanismassemblyDSP boardCard wiresCard wireTunerBarrierCN1CN591CN592eRear panelHGTH-A751-8 (No.

44、22009)2.1.6 Removing the main board (See Figs.12 and 13.) Remove the top cover. Remove the DSP board. Remove the tuner.(1) From the top side of the main body, disconnect the cardwires from the connectors (CN201, CN202, CN204,CN206-CN209) on the main board. (See Fig.12.)(2) Remove the screw J and two

45、 screws K attaching the mainboard. (See Fig.12.)(3) From the back side of the main body, remove the fivescrews L attaching the main board. (See Fig.13.)Fig.12Fig.132.1.7 Removing the amplifier board (See Figs.14 to 16.) Remove the top cover.(1) From the top side of the main body, disconnect the card

46、wires from the connectors CN701 and CN702 on the am-plifier board (See Fig.14.)(2) Remove the three screws M attaching the amplifier board.(See Fig.14.)(3) From the back side of the main body, remove the fourscrews N attaching the amplifier board. (See Fig.15.)(4) Disconnect the connector CN703 on t

47、he amplifier board,take out the amplifier board. (See Fig.14.)(5) Remove the six screws P attaching the heat sink to the am-plifier board. (See Fig.16.)Fig.14Fig.15Fig.16Card wiresCN206CN204CN201CN202CN207CN208 CN209Card wiresKJKMain boardRear panelLAmplifier boardCN703CN702CN701MMRear panelNAmplifi

48、er boardPPPHeat sinkTH-A75(No.22009)1-92.1.8 Removing the fan motor (See Figs.17 and 18.) Remove the top cover. Remove the amplifier board.(1) From the top side of the main body, remove the fan cover.(See Fig.17.)(2) Remove the tie band banding the fan motor wire and thendisconnect the fan motor wir

49、e from the connector CN174on the power board. (See Fig.17.)(3) Remove the screw Q and screw R attaching the fan brack-et. (See Fig.17.)(4) Remove the two screws S attaching the fan motor to thefan bracket. (See Fig.18.)Reference:When attaching the screw Q, attach the lug wire of thefront panel assembly at the same time.Fig.17Fig.182.1.9 Removing the power board (See Fig.19.) Remove the top cover. Remove the amplifier board.(1) From the top