JVC-THA75-ddcs-sm维修电路原理图.pdf

SERVICE MANUAL COPYRIGHT 2003 VICTOR COMPANY OF JAPAN, LTD. No.22009 2003/02 TH-A75 DVD DIGITAL CINEMA SYSTEM 22009200302 TH-A75 TABLE OF CONTENTS 1Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 2Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 3Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15 4Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16 STANDBY COMPACT SUPER VIDEO D I G I T A L E X P R O L O G I C PROGRESSIVE PHONES SOURCE VOLUME RMSTHA75U DVD CINEMA SYSTEM CHANNEL/ZOOMVOLUMETV VOL TUNING STOP DIMMER PAUSE FF/ /REW TV/VIDEOMUTING REC PLAY DOWNUP MEMORYSTROBE DVDVCR 1 AUDIO VCR/DBS ANGLE FM/AM SUBTITLEDECODE RETURNDIGEST VFP TOP MENUMENU CONTROLEFFECT S.WFR TEST SLEEP TV VCR SETTING TV RETURN ENTER ON SCREEN CHOICE FM MODE 123 456 789 100+10 100+ TVAUDIO VCR SOUND AUDIO/ TV/VCR CATV/DBS PROGRESSIVE SURROUNDOFFDSP CENTER + + + + SURR-LSURR-RS-BACK + ADJUST O.T. REPLAY XV-THA75 SP-XSA75 SP-WA75 SP-XCA75 Area Suffix US - Singapore UP - Korea UT - Taiwan UX - Saudi Arabia RadioFans.CN 收音机爱 好者资料库 TH-A75 1-2 (No.22009) SECTION 1 Important Safety Precautions 1.1 Safety Precautions (1) 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 to the original design unless authorized in writing by the man- ufacturer. Replacement parts must be identical to those used in the original circuits. Services should be per- formed by qualified personnel only. (2) Alterations of the design or circuitry of the product should not be made. Any design alterations 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 special safety-related characteristics. These characteris- tics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by us- ing replacement components rated for higher voltage, watt- age, etc. Replacement parts which have these special safety characteristics 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 the Parts List in the Service Manual. The use of a substitute re- placement which does not have the same safety character- istics as the recommended replacement parts shown in the Parts 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 from live parts, high temperature parts, moving parts and/or sharp edges for the 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 reassembling. (5) Leakage shock hazard testing) After reassembling the product, 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 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, particular- ly any exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage cur- rent must not exceed 0.5mA AC (r.m.s.). Alternate check method Plug 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 ohm 10W resistor paralleled by a 0.15 F AC-type capacitor between an exposed metal part and a known 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 outlet 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.). 1.2 Warning (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 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. 1.3 Caution Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of pre- forming repair of this system. 1.4 Critical parts for safety In regard with component parts appearing on the 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 the manufacturer. (Except the JC version) RadioFans.CN 收音机爱 好者资料库 TH-A75 (No.22009)1-3 1.5 Preventing static electricity Electrostatic 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 prevent damage by static electricity Static 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 workbench Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it. (2) Ground yourself Use 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 and 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.) Do not use a tester to check the condition of the laser diode in the optical pickup. The testers internal power source can easily destroy 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 optical 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 time when attaching it to the connector. (3) Handle the flexible cable carefully as it may break when subjected to strong force. (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 disconnected 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 assembly CN101 DVD servo board Short land sections Flexible wire TH-A75 1-4 (No.22009) 1.8 Important for laser products (1) CLASS 1 LASER PRODUCT (2) DANGER : Invisible laser radiation when open and inter lock failed or defeated. Avoid direct exposure to beam. (3) CAUTION : There are no serviceable parts inside the Laser 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 the safety interlocks have failed or are de feated. 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 radiation exposure. CAUTION Please use enough caution not to see the beam directly or touch it in case of anadjustment or operation check. VARNING Osynlig laserstrlning r denna del r ppnad och sprren r urkopplad. Betrakta ej strlen. VARO Avattaessa ja suojalukitus ohitettaessa olet alttiina nkymt- tmlle lasersteilylle. l katso steeseen. ADVARSEL Usynlig laserstrling ved bning, nr sikkerhedsafbrydere er ude af funktion. Undg udsasttelse for strling. ADVARSEL Usynlig laserstrling ved pning, nr sikkerhetsbryteren er avs- lott. unng utsettelse for strling. REPRODUCTION AND POSITION OF LABELS WARNING LABEL CLASS 1 LASER PRODUCT TH-A75 (No.22009)1-5 SECTION 2 Disassembly method 2.1 Main body section 2.1.1Removing the top cover (See Figs.1 to 4.) (1) From the right and left sides of the main body, remove the four screws A attaching the top cover. (See Figs.1 and 2.) (2) From the back side of the main body, remove the two screws B attaching the top cover. (See Fig.3.) (3) Lift the rear section of the top cover, slide the top cover slightly in the direction of the arrow. (See Fig.4.) (4) Disengage the engagement sections a of the top cover from the main body. (See Fig.4.) Fig.1 Fig.2 Fig.3 Fig.4 Top cover A Top cover A Rear panel Top cover B Top cover a TH-A75 1-6 (No.22009) 2.1.2Removing 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 of the 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 direction of the arrow and then remove the tray fitting assembly. (See Fig.6.) (4) Return the tray into the DVD mechanism assembly. (5) From the bottom side of the main body, remove the four screws C attaching the front panel assembly. (See Fig.7.) (6) From the top side of the main body, remove the two screws D attaching the front panel assembly. (See Fig.8.) (7) Disconnect the card wires from the connectors CN206 and CN207 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 the front panel assembly in the direction of the arrow 1, remove the front panel assembly in the direction of the arrow 2. (See Fig.8.) Reference: In the assembly, through the card wire in the barrier and then hold the card wire to the sections d of the barrier. (See Fig.8.) Fig.5 Fig.6 Fig.7 Fig.8 Slide cam Front panel assembly b Tray Tray Tray fitting assembly Front panel assembly Front panel assembly Chassis base C Main board Front panel assembly Lug wire Hook c Barrier CN207 2 1 CN206 d D E Hook c 1 TH-A75 (No.22009)1-7 2.1.3Removing the DVD mechanism assembly (See Fig.9.) Remove the top cover. Remove the front panel assembly. (1) From the top side of the main body, remove the barrier. (2) Disconnect the card wires from the connectors CN208 and CN209 on the main board. (3) Remove the three screws F attaching the DVD mechanism assembly. (4) Take out the DVD mechanism assembly from the chassis base. Fig.9 2.1.4Removing the DSP board (See Figs.10 and 11.) Remove the top cover. (1) From the top side of the main body, disconnect the card wires from the connectors CN591 and CN592 on the DSP board. (See Fig.10.) (2) From the back side of the main body, remove the three screws G attaching the DSP board. (See Fig.11.) (3) Remove the DSP board from the section e of the barrier, take out the DSP board. (See Fig.10.) Reference: When attaching the DSP board, hang the DSP board to the section e of the barrier. (See Fig.10.) 2.1.5Removing the tuner (See Figs.10 and 11.) Remove the top cover. (1) From the top side of the main body, disconnect the card wire from the connector CN1 on the tuner. (See Fig.10.) (2) From the back side of the main body, remove the two screws H attaching the tuner. (See Fig.11.) Fig.10 Fig.11 Main board CN209 CN208 F F Card wire Card wire Barrier Chassis base DVD mechanism assembly DSP board Card wires Card wire Tuner Barrier CN1 CN591 CN592 e Rear panel H G TH-A75 1-8 (No.22009) 2.1.6Removing 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 card wires from the connectors (CN201, CN202, CN204, CN206-CN209) on the main board. (See Fig.12.) (2) Remove the screw J and two screws K attaching the main board. (See Fig.12.) (3) From the back side of the main body, remove the five screws L attaching the main board. (See Fig.13.) Fig.12 Fig.13 2.1.7Removing the amplifier board (See Figs.14 to 16.) Remove the top cover. (1) From the top side of the main body, disconnect the card 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 four screws N attaching the amplifier board. (See Fig.15.) (4) Disconnect the connector CN703 on the 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.14 Fig.15 Fig.16 Card wires CN206 CN204 CN201 CN202 CN207 CN208CN209 Card wires KJ K Main board Rear panel L Amplifier board CN703 CN702CN701 M M Rear panel N Amplifier board PP P Heat sink TH-A75 (No.22009)1-9 2.1.8Removing 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 then disconnect the fan motor wire from the connector CN174 on the power board.