LG-DVB418-cd-sm 维修电路原理图.pdf

CONTENTSSECTION 1 . . . .SUMMARYSECTION 2 . . . .CABINET & MAIN CHASSISSECTION 3 . . . .ELECTRICALSECTION 4 . . . .MECHANISMSECTION 5 . . . .REPLACEMENT PARTS LISTRadioFans.CN 收音机爱 好者资料库SECTION 1SUMMARYCONTENTSPRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS. 1-3SERVICING PRECAUTIONS. 1-4 General Servicing Precautions Insulation Checking Prodedure Electrostatically Sensitive DevicesSPECIFICATIONS. 1-51-2RadioFans.CN 收音机爱 好者资料库1-3CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY,NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFAC-TURERS APPROVAL. UNAUTHORIZED MODIFICATIONS WILL NOT ONLYVOID THE WARRANTY, BUT MAY LEAD TO YOUR BEING LIABLE FOR ANYRESULTING PROPERTY DAMAGE OR USER INJURY.SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOU ARETHOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWING SAFETYCHECKS AND SERVICING GUIDELINES. TO DO OTHERWISE,INCREASES THE RISK OF POTENTIAL HAZARDS AND INJURY TO THEUSER.WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTEC-TION FROM A.C. LINE SHOCK.SAFETY CHECKSAFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN CORRCTED. ACHECK SHOULD BE MADE OF THE FOLLOWING.SUBJECT : FIRE & SHOCK HAZARD1. BE SURE THAT ALL COMPONENTS ARE POSITIONED IN SUCH A WAYAS TO AVOID POSSIBILITY OF ADJACENT COMPONENT SHORTS.THIS IS ESPECIALLY IMPORTANT ON THOSE MODULES WHICH ARETRANSPORTED TO AND FROM THE REPAIR SHOP.2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICESSUCH AS INSULATORS, BARRIERS, COVERS, SHIELDS, STRAIN RELIEFS, POWER SUPPLY CORDS, AND OTHER HARDWARE HAVEBEEN REINSTALLED PER ORIGINAL DESIGN. BE SURE THAT THESAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEENDEFEATED.3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLE COLDSOLDER JOINTS, SOLDER SPLASHES OR SHARP SOLDER POINTS.BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE OR DETERIORATIONTO PARTS AND COMPONENTS. FOR FRAYED LEADS, DAMAGEDINSULATION (INCLUDING A.C. CORD). AND REPLACE IF NECESSARYFOLLOW ORIGINAL LAYOUT, LEAD LENGTH AND DRESS.5. NO LEAD OR COMPONENT SHOULD TOUCH A RECIVING TUBE ORA RESISTOR RATED AT 1 WATT OR MORE. LEAD TENSION AROUNDPROTRUNING METAL SURFACES MUST BE AVOIDED.6. ALL CRITICAL COMPONENTS SUCH AS FUSES, FLAMEPROOFRESISTORS, CAPACITORS, ETC. MUST BE REPLACED WITH EXACTFACTORY TYPES, DO NOT USE REPLACEMENT COMPONENTSOTHER THAN THOSE SPECIFIED OR MAKE UNRECOMMENDED CIR-CUIT MODIFICATIONS.7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C.LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF THE CABI-NET, (THE CHANNEL SELECTOR KNOB, ANTENNA TERMINALS. HAN-DLE AND SCREWS) TO BE SURE THE SET IS SAFE TO OPERATEWITHOUT DANGER OF ELECTRICAL SHOCK. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS TEST USE AN A.C. VOLT-METER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, INTHE FOLLOWING MANNER; CONNECT A 1500 OHM 10 WATT RESIS-TOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITORBETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CON-DUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME.MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500 OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUGAND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75VOLTS R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANYVALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCKHAZARD AND MUST BE CORRECTED IMMEDIATELY.SUBJECT: GRAPHIC SYMBOLSTHE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHINAN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THESERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED“DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAG-NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIAN-GLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TOTHE PRESENCE OF IMPORTANT SAFETY INFORMATION INSERVICE LITERATURE.SUBJECT : X-RADIATION1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PER-SONNEL COVER THE SUBJECT OF X-RADIATION. THE ONLY POTEN-TIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PIC-TURE TUBE. HOWEVER, THIS TUBE DOES NOT EMIT X-RAYS WHENTHE HIGH VOLTAGE IS AT THE FACTORY SPECIFIED LEVEL. THE PROPER VALUE IS GIVEN IN THE APPLICABLE SCHEMATIC. OPERA-TION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PIC-TURE TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIR-CUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIR-ABLE LEVELS.2. ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BEUSED. DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD INCOLOR SETS, ALWAYS RE-INSTALL THEM.3. IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE ANACCURATE AND RELIABLE HIGH VOLTAGE METER. THE CALIBRATION OF THE METER SHOULD BE CHECKED PERIODICALLYAGAINST A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLEAT YOUR DISTRIBUTOR.4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLYTHERE IS NO POSSIBILITY OF AN X-RADIATION PROBLEM. EVERYTIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS SHOULDBE RUN UP AND DOWN WHILE MONITORING THE HIGH VOLTAGEWITH A METER TO BE CERTAIN THAT THE HIGH VOLTAGE DOESNOT EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATINGCORRECTLY, WE SUGGEST THAT YOU AND YOUR SERVICE ORGA-NIZATION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGU-LATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCE-DURE. AND THAT THE HIGH VOLTAGE READING BE RECORDER ONEACH CUSTOMERS INVOICE.5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS INA PRODUCT WITH A PROBLEM OF EXCESSIVE HIGH VOLTAGE,AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE ANDTHE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCTLONGER THAN IS NECESSARY TO LOCATE THE CAUSE OF EXCESSIVE VOLTAGE.6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES DESCRIBED IN THE APPROPRIATE SCHEMATIC AND DIAGRAMS(WHERE USED).SUBJECT: IMPLOSION1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTEGRAL IMPLOSION PROTECTION SYSTEM, BUT CARE SHOULD BETAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOIDSCRATCHING THE TUBE. IF SCRATCHED REPLACE IT.2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.SUBJECT : TIPS ON PROPER INSTALLATION1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBY-HOLE OR CLOSELY FITTING SHELF SPACE. OVER OR CLOSE TOHEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW.2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIOINSTALLATIONS WHERE DEW IS A FACTOR, NEAR STEAM RADIA-TORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.3. AVOID PALCEMENT WHERE DRAPERIES MAY OBSTRUCT REARVENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC-ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHTOBSTRUCT VENTILATION.4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMER-CIAL MOUNTING KIT. MUST FOLLOW THE FACTORY APPROVED MOUNTING INSTRUCTIONS A PRODUCT MOUNTED TO A SHELF ORPLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENTTHICKNESS IN SPACERS) TO PROVIDE ADEQUATE AIR FLOW ACROSS THE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERSMUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGETEST ON CUSTOMIZED INSTALLATIONS.5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ONSLOPING SHELF OR A TILTED POSITION, UNLESS THE PRODUCT ISPROPERLY SECURED.6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITSMOUNTING TO THE CART. CAUTION THE CUSTOMER ON THE HAZ-ARDS OF TRYING TO ROLL A CART WITH SMALL CASTERS ACROSSTHRESHOLDS OR DEEP PILE CARPETS.7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STANDWHICH HAS NOT BEEN LISTED BY UNDERWRITERS LABORATORIES, INC. FOR USE WITH THEIR SPECIFIC MODEL OF TELEVISION RECEIVER OR GENERICALLY APPROVED FOR USE WITH T.V.S OFTHE SAME OR LARGER SCREEN SIZE.8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS, EXPLAIN THAT A FOREST OF EXTENSIONS SPROUTING FROM A SIN-GLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TOHOME AND FAMILY.PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTSA.C. VOLTMETERGOOD EARTH GROUNDSUCH AS THE WATERPIPE. CONDUIT. ETCPLACE THIS PROBEON EACH EXPOSEDMETAL PART1-4SERVICING PRECAUTIONSCAUTION : Before servicing the DVD covered by this servicedata and its supplements and addends, read and follow theSAFETY PRECAUTIONS. NOTE : if unforeseen circum-stances create conflict between the following servicing pre-cautions and any of the safety precautions in this publica-tions, always follow the safety precautions.Remembers Safety First:General Servicing Precautions1. Always unplug the DVD AC power cord from the ACpower source before:(1)Removing or reinstalling any component, circuit board, module, or any other assembly.(2)Disconnection or reconnecting any internal electricalplug or other electrical connection.(3)Connecting a test substitute in parallel with an elec-trolytic capacitor.Caution : A wrong part substitution or incorrect polarity installation of electrolytic capacitors may resultin an explosion hazard.2. Do not spray chemicals on or near this DVD or any ofits assemblies.3. Unless specified otherwise in this service data, cleanelectrical contacts by applying an appropriate contact cleaning solution to the contacts with a pipe cleaner,cotton-tipped swab, or comparable soft applicator.Unless specified otherwise in this service data, lubricationof contacts is not required.4. Do not defeat any plug/socket B+ voltage interlocks withwhitch instruments covered by this service manual mightbe equipped.5. Do not apply AC power to this DVD and/or any of itselectrical assemblies unless all solid-state device heatsinks are cerrectly installed.6. Always connect test instrument ground lead to theappropriate ground before connection the test instrumentpositive lead. Always remove the test instrument ground lead last.Insulation Checking ProcedureDisconnect the attachment plug from the AC outlet and turnthe power on. Connect an insulation resistance meter(500V)to the blades of the attachment plug. The insulation resis-tance between each blade of the attachment plug and acces-sible conductive parts (Note 1) should be more than 1M-ohm.Note 1 : Accessible Conductive Parts including Metal pan-els, Input terminals, Earphone jacks, etc.Electrostatically Sensitive (ES) DevicesSome semiconductor (solid state) devices can be damagedeasily by static electricity. Such components commonly arecalled Electrostatically Sensitive (ES) Devices. Examples oftypical ES devices are integrated circuits and some fieldeffect transistors and semiconductor chip components.The following techniques should be used to help reduce theincidence of component damage caused by static electricity.1. Immediately before handling any semiconductor compo-nent or semiconductor-equipped assembly, drain off anyelectrostatic charge on your body by touching a knownearth ground. Alternatively, obtain and wear a commer-cially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under test.2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.3. Use only a grouned-tip soldering iron to solder or unsolderES devices.4. Use only an anti-static solder removal device. Somesolder removal devices not classified a “anti-static” cangenerate electrical charges sufficient to damage ES devices.5. Do not use freon-propelled chemicals. These cangenerate electrical charge sufficient to damage ESdevices.6. Do not remove a replacement ES device from its protective package until immediately before you are ready toinstall it. (Most replacement ES devices are packaged withleads electrically shorted together by conductive foam,aluminum foil, or comparable conductive material).7. Immediately before removing the protective material fromthe leads of a replacement ES device, touch the protectivematerial to the chassis or circuit assembly into which thedevice will be installed.Caution : Be sure no power is applied to the chassis orcircuit, and observe all other safety precautions.8. Minimize bodily motions when handling unpackaged replacement ES devices. (Normally harmless motion such as the brushing together of your clothes fabric or the liftingof your foot from a carpeted floor can generate static elec-tricity sufficient to damage an ES device.)1-5SPECIFICATIONS GENERALPower requirements:AC 100-240 V , 50/60 HzPower consumption:12W Dimensions (Approx.):430 x 39 x 242 mm (W x H x D) without foot Weight (Approx.): 2.2 kgOperating temperature:5 C to 35 C (41 F to 95 F)Operating humidity: 5 % to 90 % OUTPUTSVIDEO OUT:1 Vp-p 75 , sync negative, RCA jack x 1/ SCART (TO TV)AUDIO OUT:2.0 Vrms (1 KHz, 0 dB), 600 , RCA jack (L, R) x 1/ SCART (TO TV)DIGITAL OUT (COAXIAL):0.5 V (p-p), 75 , RCA jack x 1 SystemLaser: Semiconductor laser, wavelength 650 nmSignal system: PAL / NTSCFrequency response:DVD (PCM 96 kHz): 8 Hz to 44 kHz DVD (PCM 48 kHz): 8 Hz to 22 kHzCD: 8 Hz to 20 kHzSignal-to-noise ratio:More than 100 dB (ANALOG OUT connectors only)Harmonic distortion: Less than 0.008%Dynamic range:More than 90 dB (DVD/CD) AccessoriesVideo cable (1), Audio cable (1), Remote control (1), Batteries (2)2-1SECTION 2CABINET & MAIN CHASSISCONTENTSEXPLODED VIEWS.2-21. Cabinet and Main Frame Section.2-22. Packing Accessory Section.2-32-2EXPLODED VIEWS1. Cabinet and Main Frame SectionA43A44A00A45A47A48A46280452A42283260320465467465463463463463463280300463452A49261261A54321BCD2-32. Packing Accessory SectionBATTERY808PACKING SHEET804PACKINGOPTIONAL PARTS803806820OWNERS MANUALRF CABLE810 CABLE SET ASSY801REMOCON900BOX CARTON802PACKING803811812PLUG ASSY 1WAY(YELLOW)PLUG ASSY 1WAY(BLACK)PLUG ASSY 2WAY3-1SECTION 3ELECTRICALCONTENTSFEATURES FOR MEMORY CARD READ.3-2ELECTRICAL TROUBLESHOOTING GUIDE.3-31. Power check flow.3-32. System operation flow .3-43. Test & debug flow.3-5DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING.3-111. SYSTEM 27MHz CLOCK, RESET, FLASH R/W SIGNAL. .3-112. SDRAM CLOCK.3-133. TRAY OPEN/CLOSE SIGNAL.3-134. SLED CONTROL RELATED SIGNAL(NO DISC CONDITION).3-145. LENS CONTROL RELATED SIGNAL(NO DISC CONDITION).3-146. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION).3-157. DISC TYPE JUDGEMENT WAVEFORM.3-158. FOCUS ON WAVEFORM.3-179. SPINDLE CONTROL WAVEFORM(NO DISC CONDITION.3-1810. TRACKING CONTROL RELATED SIGNAL(System checking).3-1911. MT1389 AUDIO OPTICAL AND COAXIAL OUTPUT (SPDIF).3-2012. MT1389 VIDEO OUTPUT WAVEFORM.3-2013. MT1389 AUDIO OUTPUT TO AUDIO DAC.3-2114. AUDIO OUTPUT FROM AUDIO DAC .3-22BLOCK DIAGRAMS.3-231. Overall Block Diagram .3-232. Power(SMPS) Block Diagram.3-243. SERVO Block Diagram.3-254. MPEG & MEMORY Block Diagram.3-265. VIDEO & AUDIO Block Diagram.3-27CIRCUIT DIAGRAMS.3-281. Power(SMPS) Circuit DIAGRAM.3-282. AV/JACK Circuit DIAGRAM.3-303. SYSTEM Circuit DIAGRAM .3-324. DRIVER Circuit DIAGRAM.3-335. TIMER Circuit DIAGRAM.3-366. 5.1CH, SCART Circuit DIAGRAM .3-38 CIRCUIT VOLTAGE CHART .3-40PRINTED CIRCUIT DIAGRAMS.3-421. MAIN P.C.BOARD.3-422. KEY P.C.BOARD.3-443. TIMER P.C.BOARD.3-454. SCART & 5.1CH P.C.BOARD(OPTIONAL PART).3-465. SMPS P.C.BOARD.3-473-2FEATURES FOR MEMORY CARD READ1. There will be a key in front panel to convert mode from disc ( or VCR or AUX ) to memory, vice versa.2. In disc mod