LG-LGDVT418-cdrec-sm 维修电路原理图.pdf

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1、DVD/CD RECEIVERSERVICE MANUALP/N : 3829RDT044UAUGUST, 2004MODEL: LGDVT418SERVICE MANUAL MODEL: LGDVT418CD-R/RWRadioFans.CN 收音机爱 好者资料库- 1-1 -CONTENTS SECTION 1.GENERAL SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ESD PRECAUTIO

2、NS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5 SECTION 2. AUDIO PART ELECTRICAL TROUBLESHOOTING GUIDE .

3、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4、 . . . . . . . . . . . 2-7 WIRNG DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21 PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23 SECTION 3.DVD PART DVD PART E

5、LECTRICAL TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1 DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING . . . . . . . . . . . . . . . . .3-8 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6、 . 3-21 DVD PART SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25 SECTION 4. EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 SECTION 5. SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7、 . . . . . . . . .5-1 SECTION 6. REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1RadioFans.CN 收音机爱 好者资料库- 1-2 -SECTION 1. GENERAL SERVICING PRECAUTIONSNOTES REGARDING HANDLING OF THE PICK-UP1. Notes for transport and storage1) The pick-up should always be left in its c

8、onductive bag until immediately prior to use.2) The pick-up should never be subjected to external pressure or impact.2. Repair notes1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.2) The pick-up should always be handled correctly and carefully,

9、 taking care to avoid external pressure andimpact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/ordamage to the printed-circuit board.3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reasonthe

10、adjustment point and installation screws should absolutely never be touched.4) Laser beams may damage the eyes!Absolutely never permit laser beams to enter the eyes!Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.5) Cleaning the lens surfaceIf the

11、re is dust on the lens surface, the dust should be cleaned away by using an air bush (such as usedfor camera lens).The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cottonswab should be used, taking care not to distort this.6) Never attempt to disassemble the pick-u

12、p.Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab.(Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too muchof this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.Storage

13、in conductive bagDrop impactNEVER look directly at the laser beam, and dont let contact fingers or other exposed skin.MagnetHow to hold the pick-upConductive SheetCotton swabPressurePressure- 1-3 -NOTES REGARDING COMPACT DISC PLAYER REPAIRS1. Preparations1) Compact disc players incorporate a great m

14、any ICs as well as the pick-up (laser diode).These componentsare sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, componentscan be damaged, and for that reason components should be handled with care.2) The pick-up is composed of many optical compo

15、nents and other high-precision components. Care must betaken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong magnet-ism is present, or where there is excessive dust.2. Notes for repair1) Before replacing a component part, first disconnect the power supp

16、ly lead wire from the unit2) All equipment, measuring instruments and tools must be grounded.3) The workbench should be covered with a conductive sheet and grounded.When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This isbecause there is the possibility

17、of damage by static electricity.)4) To prevent AC leakage, the metal part of the soldering iron should be grounded.5) Workers should be grounded by an armband (1M )6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent sta-tic electricity change

18、s in the clothing to escape from the armband.7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.Resistor(1 Mohm)ConductiveSheetResistor(1 Mohm)Armband- 1-4 - ESD PRECAUTIONSElectrostatically Sensitive Devices (ESD)Some semiconductor (solid state) devices can be

19、damaged easily by static electricity. Such componentscommonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integratedcircuits and some field-effect transistors and semiconductor chip components.The following techniques shouldbe used to help reduce the inc

20、idence of component damage caused by static electricity.1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain offany electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear acommercially available discharging w

21、rist strap device, which should be removed for potential shock reasonsprior to applying power to the unit under test.2. After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive sur-face such as aluminum foil, to prevent electrostatic charge buildup or expos

22、ure of the assembly.3. Use only a grounded-tip soldering iron to solder or unsolder ESD devices.4. Use only an anti-static solder removal device. Some solder removal devices not classified as anti-static cangenerate electrical charges sufficient to damage ESD devices.5. Do not use freon-propelled ch

23、emicals.These can generate electrical charges sufficient to damage ESDdevices.6. Do not remove a replacement ESD device from its protective package until immediately before you areready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together byconductive fo

24、am, aluminum foil or comparable conductive materials).7. Immediately before removing the protective material from the leads of a replacement ESD device, touch theprotective material to the chassis or circuit assembly into which the device will by installed.CAUTION : BE SURE NO POWER IS APPLIED TO TH

25、E CHASSIS OR CIRCUIT, AND OBSERVE ALLOTHER SAFETY PRECAUTIONS.8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motionsuch as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can gen-erate static electricity

26、sufficient to damage an ESD device).CAUTION. GRAPHIC SYMBOLSTHE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, ISINTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DAN-GEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OFELECTRIC SHO

27、CK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THESERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICELITERATURE.- 1-5 - SPECIFICATIONS- 1-6 -MEMO- 2-1 -ELECTRICAL TROUBLESHOOTING GUIDEINSERTPOWER CORD.TURN ONTHE RED LED?IS POWER ON?CHECK POWER P

28、LUGAND POWER SUPPLY CIRCUIT .DOES INITIALREAD WORK?DOES IT PLAY?YESNOYESYESOKNOYESNONOCHECK POWER SUPPLY CIRCUIT .CHECK LASER CIRCUIT .CHECK TRACKING SERVO CIRCUIT.TURN POWER ON.CHECK FOCUS CIRCUIT.CHECK DISC.DOES IT OUTPUTAUDIO?YESNOCHECK AUDIO CIRCUIT.1. Power check flowSECTION 2. AUDIO PART- 2-2

29、-2.AUDIO .COM CIRCUITPOWER ONDoes it appearDVD Error atFLD?Does AV 1/2, TV, AUDIO, OPTICAL IN, COAXIAL IN, FM87.5 appear at FLD?CheckConnector(PN902)ifis normally.Check power partof Main B/D.Check oscillatorof x101.Check if IC101PIN1 is High.Check if IC101PIN11 is High.Check if IC101 PIN17, 46, 72,

30、90 is high(5V).Check if IC101PIN26 is High.Replace IC101.Does CD/DVDappear at FLD?Reconnet it.Refer to SMPSOK.Refer to oscillatorCircuit.Check DVD Reset Waveform.Check IC101 Reset Wavefrom.Check 5V line.Check Power dection Circuit.Does LOADINGappear at FLD?Does no Disc orTime appear at FLD?Check if

31、DVD an Audio Micom Interface is OK.Check power.Check DVD Module.Check SMPS.- 2-3 -3.FRONT CIRCUIT (1/2)- 2-4 -4.FRONT CIRCUIT (2/2) BLOCK DIAGRAM2-52-62-72-8 SCHEMATIC DIAGRAMS FRONT SCHEMATIC DIAGRAM2-92-10 MICOM SCHEMATIC DIAGRAM2-112-12 I/O SCHEMATIC DIAGRAM2-132-14 DSP SCHEMATIC DIAGRAM2-152-16

32、AMP SCHEMATIC DIAGRAM2-172-18 SMPS-WIDE SCHEMATIC DIAGRAM2-192-20 POWER SCHEMATIC DIAGRAM2-212-22 WIRING DIAGRAMS2-232-24 PRINTED CIRCUIT DIAGRAMS MAIN P.C. BOARD (COMPONENT SIDE)2-252-26 MAIN P.C. BOARD (SOLDER SIDE)2-272-28 FRONT P.C.BOARD (SOLDER SIDE) FRONT P.C.BOARD (COMPONENT SIDE)2-292-30 POW

33、ER P.C.BOARD2-312-32MEMOMEMO- 3-1 -1. Power check flowELECTRICAL TROUBLESHOOTING GUIDESECTION 3. DVD PART - 3-2 -2. System operation flowPower On1. 8032 initializes SERVO, DSP & RISC registers2. Write RISC code to SDRAM3. Reset RISCShow LOGOTray Closed?Tray Close to Closed position NOSLED at InnerSi

34、de ?SLED Moves to Inner Positi onNOYESYESReci eveOPEN/CLOSEKey?1. Execute Pressed Key & IR Key2. System operation Routine LoopNO1. Stop Playback & Open Tray2. Display tray open message & LOGOReceiveCLOSE Key?NOYESYES1. Judge whether have disc and disc type2. Jump to related disc reading procedure- 3

35、-3 -3.Test & debug flowTESTCheck the AC VoltagePower PCBA(110V or 220V)NOReplace power PCBA orAC transformer.YESSwitch on the Power PCBAIs the DC Voltageoutputs OK?(5V,1.8V,3.3V,8V,12V)Repair or Replace Power PCBANOMake sure the main PCBA dontshort on VCCs and switch it on.YESIs 3.3V and 1.8V DCoutp

36、uts normal on mainPCBA?Check the regulators or related diodes.NOYESConnect to PC RS232 Cable andupdate the FLASH memory code.Update FLASHsuccessfully?AYESNO1. Check 27MHz system clock.2. Check system reset circuit.3. Check FLASH R/W enable signal PRD,RWR.4. Check RS232 SIGNALS.5. Check FLASH Memory

37、related circuit.- 3-4 -ARESET or Power On.NONOYESNOYESNOYESYESBNONONOYESYESNONOYESYESYESShow LOGO?Flash Memory operatesproperly?Check connection lines between FLASH& MT1389 and the FLASH access timewhether is suitable or not.SDRAM works properly?Check connection lines betweenSDRAM & MT1389 and the S

38、DRAMis damaged.MT1389 VIDEO outputsproperly?Check the related circuit of MT1389.Have TV signal output?Check the filtering and amp circuit ofTV signal.Check AV cable connectionto TV set.Does Tray moveinside when it is notat closed position?Normal TROUT &TRIN signals?Check the load OPEN & CLOSEswitchN

39、ormal TRCLOSE &TROPEN signal?Normal LOAD+ &LOADsignal?Check the cable connectionbetween main PCBA and loader.Check the Tray control IO pins onMT1389 & IP4504.Check the Tray control amplifyingcircuit on Motor driver.- 3-5 -BNONONONONONONOYESYESYESYESYESYESYESDoesthe SLED moveto inner side when it is

40、atoutter position?Motor Driver STBYPin is High?Check the connection line ofSTBY signal.Is FMSO DC Level higherthan 1.4V?Check the related circuit ofFMSO.SL+ and SL- outputproperly?Check the amp circuit on motordriver.Check the cable connection withMECHA.Do not put in disc and trayclose.COptical Lens

41、 hasmovements for searchingFocus?Proper FOSO outputsto motor driver?Check FOSO connection onMT1389 and motor dirver.Proper F+ & F- outputs?Check the amp circuit on motordirver.Check cable connect on withpick-up head.- 3-6 -DCYESNOYESYESNONODoes spindle rotate?Proper DMSO signal onMT1389Check DMSO re

42、latedcircuit on MT1389.SP+ & SP- outputproperly?Check the spindle controlamp circuit of motordriver.Check the cable connectionbetween spindle and main PCBA.YESYESNONOLaser turns on whenreading disc?NONOYESNOYESYESNOLD01 or LD02 outputproperly?Check the laser power circuiton MT1336 and connecting top

43、ower transistor.Collector voltage ofpower transistor is OK?Check the related circuit onlaser power transistorCheck cable connection betweentransistor ouput and pick-uphead.Put disc in?Laser offDisc ID is correct?Proper RFL signalon MT1389?Check the related circuiton MT1389 RFL signal.Check LDO1 & LD

44、O2 signalYES- 3-7 -YESNO YESYESDNONONOYESNOEYESNormal TEO Signal onMT1389?Check the relatedcircuit on MT1389Track On OK?Properly TRSO signalon MT1389?T+ & T- outputproperly?Check the TRSOconnection on MT1389and motor dirver.Check the tracking controlamp circuit on motordriver.Check cable connection

45、onpick-up head.Disc is play ?Check RFO & RFLVL signal waveform.NONOYESYESYESFocus ON OK?Proper signals onA,B,C,D of MT1389Check connections betweenMT1389 and pick-up head.Check FEO signalon MT1389Check FOSO signal on MT1389Check the FOSO connection onMT1389 and motor driver.YESNO- 3-8 -Normal IR.VFD

46、 & Frontpannel key functions?Communications betweenIR.VFD Front pannel key & MT1389is n orma lly?Check communication lines onMT1389.NOYESCheck the cable connection onFront pannel.TEST ENDYESNormal Audio outputwhen disc playback?Audio PWM IC receivedcorrect data stream?Check connection between MT1379

47、& Audio PWM IC.Normal Audio PWM ICout?Check the relatedcircuit of Audio PWM IC.Check Audio filter,amplify,mutecircuit.NONONOYESYESYESENO- 3-9 -FIG 1-1FIG 1-2 DETAILS AND WAVEFORMS ON SYSTEM TESTAND DEBUGGING1. SYSTEM 27MHz CLOCK,RESET,FLASH R/W SIGNAL1) MT1379 main clock is at 27MHz(X501)2) MT1336 r

48、eset is high active- 3-10 -FIG 1-3FIG 1-43) RS232 waveform during procedure(Downloading)4) Flash R/W enable signal during download(Downloading)- 3-11 -FIG 2-1FIG 3-12. SDRAM CLOCK1) MT1379 main clock is at 27MHz(X501)3.TRAY OPEN/CLOSE SIGNAL- 3-12 -FIG 4-1FIG 5-14. SLED CONTROL RELATED SIGNAL (NO DI

49、SC CONDITION)5. LENS CONTROL RELATED SIGNAL(NO DISC CONDITION)- 3-13 -FIG 6-1FIG 7-16. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION)7. DISC TYPE JUDGEMENT W VEFORM- 3-14 -FIG 7-2 (DVD)FIG 7-3 (CD)- 3-15 -FIG 7-4 (CD)FIG 8-1 (DVD)8. FOCUS ON W VEFORM- 3-16 -FIG 8-2 (CD)FIG 9-19. SPINDLE CONTR

50、OL W VEFORM (NO DISC CONDITION)- 3-17 -10.TRACKING CONTROL RELATED SIGNAL(System checking)FIG 10-1 (DVD)FIG 10-2 (CD)- 3-18 -FIG 11-1 (DVD)FIG 12-111. MT1389 AUDIO OPTICAL AND COAXIAL INPUT (SPDIF)12. MT1389 VIDEO OUTPUT WAVEFORM1)100%- 3-19 -ADAT03FIG 12-2FIG 13-12) COMPOSITE VIDEO SIGNAL13. MT1389