LG-LX220-cs-sm 维修电路原理图.pdf

- 1- 1 -CONTENTSSECTION 1. GENERAL SERVICING PRECAUTIONS.1- 2 ESD PRECAUTIONS.1- 4 SPECIFICATION.1- 5SECTION 2. TROUBLESHOOTING ADJUSTMENTS.2- 1 TROUBLESHOOTING . 2- 3 WAVEFORMS OF MAJOR CHECK POINT. 2- 7 BLOCK DIAGRAM.2- 16 SCHEMATIC DIAGRAMS.2- 18 WIREING DIAGRAM. 2- 26 PRINTED CIRCUIT DIAGRAMS. 2- 28 INTERNAL BLOCK DIAGRAM OF ICs . 2- 39 PRINTED CIRCUIT DIAGRAMS.2- 53SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION.3- 1SECTION 4. SPEAKER SECTION SPEAKER SECTION. 4- 1SECTION 5. REPLACEMENT PARTS LIST REPLACEMENT PARTS LIST.5- 1RadioFans.CN 收音机爱 好者资料库SERVICING PRECAUTIONSNOTES REGARDING HANDLING OF THE PICK-UPNotes for transport and storage1) The pick- up should always be left in its conductive bag until immediately prior to use.2) The pick- up should never be subjected to external pressure or impact.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, 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 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 there 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, acotton swab should be used, taking care not to distort this.6) Never attempt to disassemble the pick- up.Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab. (Do- 1- 2 -Storage in conductive bagDrop impactNEVER look directly at the laser beam, and dont letcontact fingers or other exposed skin.MagnetHow to hold the pick- upPressurePressureCotton swabConductive SheetSECTION 1. GENERALRadioFans.CN 收音机爱 好者资料库NOTES REGARDING COMPACT DISC PLAYER REPAIRSPreparations1) Compact disc players incorporate a great many ICs as well as the pick- up (laser diode). Thesecomponents are sensitive to, and easily affected by, static electricity. If such static electricity is highvoltage, components can be damaged, and for that reason components should be handled with care.2) The pick- up is composed of many optical components and other high- precision components. Care mustbe taken, therefore, to avoid repair or storage where the temperature of humidity is high, where strongmagnetism is present, or where there is excessive dust.Notes for repair1) Before replacing a component part, first disconnect the power supply 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 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 preventstatic electricity changes 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.CLEARING MALFUNCTIONYou can reset your unit to initial status if malfunction occur(button malfunction, display, etc.).Using a pointed good conductor(such as driver), simply short the RESET jump wire on the inside of thevolume knob for more than 3 seconds. If you reset your unit, you must reenter all its settings(stations, clock, timer)NOTE:1. To operate the RESET jump wire, pull the volume rotary knob and release it.2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord.- 1- 3 -ArmbandConductiveSheetResistor(1 Mohm)Resistor(1 Mohm)VOLUME KNOBUPDOWNVOLUMERESET jump wireESD PRECAUTIONSElectrostatically Sensitive Devices (ESD)Some semiconductor (solid state) devices can be 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 incidence 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 wrist 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 conductivesurface such as aluminum foil, to prevent electrostatic charge buildup or exposure 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 chemicals. 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 are readyto install it. (Most replacement ESD devices are packaged with leads electrically shorted together byconductive foam, 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 THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHERSAFETY 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 cangenerate static electricity sufficient to damage an ESD device).CAUTION. GRAPHIC SYMBOLS- 1- 4 -THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERALTRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCEOF UNINSULATED DANGEROUS VOLTAGE THAT MAY BE OF SUFFICIENTMAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TOALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETYINFORMATION IN SERVICE LITERATURE.- 2- 1 -TAPE DECK ADJUSTMENT1. AZIMUTH ADJUSTMENTFigure 1. Azimuth Adjustment Connection DiagramCH1 CH2Speaker OutPlayback ModeHeadTest TapeMTT- 114L chR chGNDDual- tracesynchroscopeElectronicVoltmeterL outR outUnit2. MOTOR SPEED ADJUSTMENTHeadUnitPN202GNDRecord/PlaybackheadTest TapeMTT- 5511Record/Playbackand Pause ModeFrequency CounterDeck ModeTest TapeTest TapeAdjustmentAdjust forRec/PauseMTT- 5511ERASE HEADL20160kHz5kHz (Auto stop)WIRE(PN201)85kHz5kHz(Auto Reverse)Figure 2. Motor Speed Adjustment Connection DiagramSECTION 2. ELECTRICAL SECTIONADJUSTMENTSThis set has been aligned at the factory and normally will not require further adjustment. As a result, it is notrecommended that any attempt is made to modificate any circuit. If any parts are replaced or if anyone tamperswith the adjustment, realignment may be necessary.IMPORTANT1. Check Power- source voltage.2. Set the function switch to band being aligned.3. Turn volume control to minimum unless otherwise noted.4. Connect low side of signal source and output indicator to chassis ground unless otherwise specified.5. Keep the signal input as low as possible to avoid AGC and AC action.Deck ModeTest TapeTest TapeAdjustmentAdjust forPalybackMTT- 114Speaker OutDECK ScrewMaximumAzimuth Screw- 2- 2 -3. TUNER ADJUSTMENTFigure 3. Tuner(S curve) Adjustment Connection DiagramUnitSignal GeneratorGNDElectronicOSCILLOSCOPEFM AntennaTerminalSpeakerItemTest PointAdjustmentAdjust forDC VoltageCheck Point TP1, TP2L1010V50mV(FM)- 2- 3 -TROUBLESHOOTING CD PARTTurn power on.Is power on?Does initial read work?Does it play?Does it output audio?Check power supply circuit.PN508 PIN8, 6.2VPN508 PIN7, 5VIC503 PIN2, 3.3VCheck the connector PN503,PN504, PN507Check the tracking servo.Check the PN508 PIN1, 3OKNOYESYESYESNONONONONONOCheck the DISK circuitCheck the LaserCheck the focus circuitCheck the TRAKING servo.NONO- 2- 4 -FAILS TO INITIAL READ AB2V5V0V5V0V1V0V1.2V0V0.8VNONONONONONONONOYESYESYESYESYESYESYESYESYESYESYESYESDisc motor turnsDoes RF waveform appear?IC501 Pin3Check the Data transferred from PN507pin8 to CD DSPCheck the Data transferred from PN507pin6 to MICOMSLDO Voltage(IC501 pin23)Check the change of SL +,SL - Voltage(IC502 pin 18, 19)Check the Voltage change of PN 507PIN2(OPEN, CLOSE)Defective connectorPN507Defective connectorPN507, DefectiveMICOMDefective connectorPN507, DefectiveIC501Defective IC501Defective IC502Defective contact PN503Defective PICK- UPDoes laser light?focus coil drive wareform.TRACKING ERROR wareformIs rotation normal?Defective IC501Defective PICK- UPIs there no dropout of RF signal?Does FA+ waveform appear atIC502 pin18?Does TE waveform appear at IC501 pin15?- 2- 5 -NONONONONONOLaser does not light.Is 3.5V applied to pin80 of IC801?Is power supplied to laser Q501?(Q501 collector: about 1.8V)Does laser current flow?(R508s voltage are 1.0V)Is data transferred fromMICOM IC ?Does voltage appear at IC502 pin18, 19?Defective MICOM.Defective MICOM.Defective connector.Defective IC501, 502 Defective slide motor and/orconnector.Defective LMT SW and/orconnector.Defective Q 501 and/or laser.Defective laser and/orconnector.Did pickup return toinnermost circular?Does it stop at inner pickcircular after shift?Is defect output from LMSW applied to pin 5 ofPN503?R5081.0VR5081.0VYESYESYESYESOPENCLOSEYESYESYESYESYESYES- 2- 6 -BNONONONONOYESYESYESYESLaser lightsDoes lens move up/down?Check the signal of FOCUSSEARCH(IC501 Pin 21)Chekc the signal of PN502pin 13, 14Does FE signal appear?(IC501 pin 13)Does DRF signal appear? (IC501 pin67)Defective IC501Defective IC502Open activator and/or connectorDefective IC501Degraded laser diodeDefective PICK- UP- 2- 7 -(CH1)(CH2)WAVEFORMS OF MAJOR CHECK POINT1. HF signal (RF signal ) waveform(IC501 pin4) during normal play 2. EFM signal (IC501 pin 3)waveformduring Normal Play3. Focus coil drive waveform(IC502 pin13) When focus search failed or there is no disc on the tray Focus coil drive waveform(FDO: IC501 pin21) andDRF(IC501 pin67) when focus search is accomplished4. Tracking coil drive waveform and TE during tracktraverse(1) When time division is 20mS/Div.1V/Div.(2) When time division 1mS/Div, 1V/Div(During forward track traverse)(3) When time division is 0.5nS/div.(During backward Track Traverse)5. Feed motor drive waveform(IC 502 pin18)During normal playCH1 : FOCUS COIL DRIVESIGNAL 2V/Div.CH2 : DRFCH1 : TRACKING COIL DRIVESIGNAL 2V/Div. (IC502 pin27)CH2 : TRACKING ERROR(TE: IC501 pin15)1V/Div.(CH1 : TRACKING COIL DRIVE (IC502 pin27)SIGNAL 2V/Div.CH2 : TRACKING ERROR (TE: IC501 pin15)1V/Div.(CH1 : TRACKING COIL DRIVE (IC502 pin27)CH2 : TRACKING ERROR (TE: IC501 pin15)(0.5V/Div.500nS/Div.(1S/Div.1V/Div.(1mS/Div.1V/Div.(0.5V/Div.5S/Div.(2S/Div.0.5V/Div.OVOVOV(CH1)(CH2)(CH1)(CH2)(CH2)OVOVOVOVOVOVOVOVOV- 2- 8 -VKK PARTDoes DC - 27V appear at PN303 Pin .OKDose - 27V appear atZD601(- )Check the TURN ONReplace the Q601Refer to power circuitOKCheck the - 27V(Lower) ofC603(- )Replace the D601,D602YESYESNONOP-SENS PART Does +5V appear at ZD702?Check the pattern of IC301 Pin .Check the waveform of D706(+).Check the R718 and replaceZD 702Replace the D706YESYESNONO2620- 2- 9 -POWER CIRCUIT Check the Fuse Check the DC output of C715(+), C716(- )Check the DC 12V Input ofIC702Check the DC 6.2Voutput of IC704Check the DC 12VOutput of IC703Check the Collector (5.6V) of Q704 (CD FUNCTION)OKReplace the Fuse Check the powerReplace the D701, D702, 703, 704Check the Pattern of IC702and IC704Check the High of IC703 pin4Replace the IC703Refer to IC401TROUBLESHOOTINGReplace the TransformerCheck the LOW ofIC401 pin8YESYESYESYESYESYESYESNONONONONO- 2- 10 -MUTEMUTING CIRCUIT (MUTE)Dose High appear at Q701, Q751 Bcheck the LOW Q701, Q751, CRefer to IC203 Troubleshooting (ONLY Q201/Q251)Check the High of Q702 EReplace the TRReplace the Q702Refer to IC301TroubleshootingYESYESYESNONONOAUDIO ABNORMALCheck the output of IC701 Pin 2, 4Check the speaker connectorCheck the FUNCTION inputterminalCheck the input of IC701 pin7, 11Check the DC 10V of IC400PIN24Check the DC 12V Output ofIC702Power checkYESYESYESYESNONO- 2- 11 -FUNCTION MODE AUDIO ABNORMALTAPECheck the signal input of IC400 pin 7, 28Refer to IC200 TroubleshootingAUXChekc the signal input of IC400, pin 1, 6Check the signal input of JK400CHECK THE SIGNAL INPUT OF IC400 PIN 3, 4Check the signal CN500 Pin 1, 3 or Referto CD TroubleshootingCheck the signal input of IC400 pin 2, 5Refer to IC102 TroubleshootingCDTUNERIC301 TROUBLESHOOTINGCheck the power supplying IC301 Pin 17, 46, 90?Refer to Power Circuit TroubleshootingCheck the P- SENSReplace the X301Check the RESET circuitCheck the High of IC301 pin26Check the oscillation of X301When power supplying to IC301 pin12.(LowHigh)Replace the IC301YESYESYESYESNONONONO- 2- 12 -Refer to IC301TroubleshootingIC203 TROUBLESHOOTINGRefer to Power Circuit TroubleshootingCheck the Data of IC301 Pin 9, 10(CDTAPE FUNCTION)Replace the IC400Check the pattern of (IC301, IC400)Check the power supplying to IC400 pin24Check the CLK Data of IC400 pin 21, 22Check the CONTROLL functionENDYESYESYESNONONOFM (TUN101)Check the 12V input of TUN101 B+ 6Check the High Voltage of TUN101 VT 5Check the OSC waveform of TUN101 Pin 8Refer to IC102 TroubleshootingCheck the 12V of Q102 E Refer to Power CircuitTrouble- shootingCheck the GND of IC103 Pin 7 Refer to IC103TroubleshootingReplace the Q102Replace the TUN101Replace the TUN101YESYESYESYESYESNONO- 2- 13 -IC102 TROUBLESHOOTINGIs power supplied to pin8Check the waveform of Pin 20, 21Check the output of Pin 16, 17ENDRefer to Power CircuitTroubleshootingCheck the FM(TUN101) & AM(L107)Replace the IC102Replace the IC102Check the Low of Pin 13Refer to IC103TroubleshootingYESYESYESYESNONONONONOIC103 TROUBLESHOOTINGCheck the power supplying to pin 17Check the oscillation of X104Check the waveform of CE, DI, DO, CLKIs the normal ? ENDRefer to Power CircuitTroubleshootingReplace the X104Check the line or refer to IC 301TroubleshootingCE: Chip EnableDI: Data Input(from u- com)DO: Data Output(to u- com)CLK: