LG-FFH286A-cs-sm 维修电路原理图.pdf

3CD CHANGERHI-FI SYSTEMSERVICE MANUALMODEL : FFH-286A/AD, FE-286ESERVICE MANUALMODEL:FFH-286A/AD, FE-286ERadioFans.CN 收音机爱 好者资料库- 1-1 -CONTENTSSECTION 1. GENERAL SERVICING PRECAUTIONS.1-2 ESD PRECAUTIONS.1-4 SPECIFICATIONS.1-5SECTION 2. ELECTRICAL ADJUSTMENTS.2-1 TROUBLESHOOTING.2-3 WAVEFORMS OF MAJOR CHECK POINT.2-7 BLOCK DIAGRAM.2-17 SCHEMATIC DIAGRAMS.2-19 WIRING DIAGRAM.2-27 PRINTED CIRCUIT DIARGAMS.2-29 INTERNAL BLOCK DIAGRAM OF ICs.2-38 REPAIRS REGARDING CD MECHANISM.2-45SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION .3-1 TAPE DECK MECHANISM: AUTO STOP DECK(OPTIONAL). 3-3 TAPE DECK MECHANISM: AUTO REVERSE DECK.3-5 CD MECHANISM.3-7SECTION 4. SPEAKER.4-1SECTION 5. REPLACEMENT PARTS LIST.5-1RadioFans.CN 收音机爱 好者资料库SECTION 1. GENERALSERVICING PRECAUTIONSNOTES REGARDING HANDLING OF THE PICK-UP1. Notes 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.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, 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. (Donot use any other liquid cleaners, because they will damage the lens.) Take care not to use too much ofthis alcohol on the swab, and do not allow the alcohol to get inside the pick-up.- 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 SheetNOTES REGARDING COMPACT DISC PLAYER REPAIRS 1. Preparations1) 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.2. 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 SYMBOLSTHE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, ISINTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED“DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OFELECTRIC SHOCK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THESERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICELITERATURE.- 1-4 - 1-5 -SPECIFICATIONSSECTION MODELFFH-286A/ADGeneralPower supplyRefer to the back panel of the unitPower consumption30WMass5.70kgExtemal dimensions(W X H X D)273X 330 X 360mmCDFrequency Response40-18000HzSignal-to-noise ratio70dBDynamic range70dBTuning Range87.5-108.0MHz or 65-74MHz, 87.5-108.0MHzIntermediate Frequency10.7 MHzFMSignal-to-noise ratio61/58dBFrequency Response60-10000HzTuning Range522-1611kHz or 530-1610kHzAMIntermediate Frequency450kHzSignal-to-noise ratio35 dBFrequency Response100-2000 HzAMPOutput Power5W + 5WT.H.D0.3%Frequency Response42-20000HzSignal-to-noise ratio80dBTAPETape Speed4.75cm/secWow Flutter0.25% (MTT-111,JIS-WTD)F.F/REW Time120sec(C-60)Frequency Response250-8000HzSignal-to-noise ratio43dBChannel Separation50dB(P/B)/45dB(R/P)Erase Ratio55dB (MTT-5511)SpeakerMODELFE-286EType1 Way 1 SpeakerImpedance4Frequency Response80-20000Hz Sound Pressure Level86dB/W(1m)Rated Input Power5WMax.Input Power10WNet Dimension(W XH XD)180 X326 X 165.8mmNet Weight1.67kgNOTE : Specification are subject to change without notice in the course of product improvement.TUNER- 1-6 -MEMO- 2-1 -TAPE DECK ADJUSTMENT1. AZIMUTH ADJUSTMENTFigure 1. Azimuth Adjustment Connection DiagramCH1 CH2Speaker OutPlayback ModeHeadTest TapeMTT-114L chR chGNDDual-tracesynchroscopeElectronicVoltmeterL outR outUnitSECTION 2. ELECTRICALADJUSTMENTSThis 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 PointAdjustmentAdjust forA Deck PlaybackMTT-114Speaker OutDECK ScrewMaximumAzimuth ScrewB Deck PlaybackMTT-114Speaker OutAzimuth ScrewMaximum2. MOTOR SPEED ADJUSTMENTFigure 2. Motor Speed Adjustment Connection DiagramHeadPlayback ModeUnitSpeaker OutGNDL outR outRecord/PlaybackheadTest TapeMTT-111Frequency CounterDeck ModeTest TapeTest PointAdjustmentAdjust forRemarkNormal SpeedMTT-111Speaker OutVR2013kHz 1%A DeckHI-SpeedMTT-111Speaker Outmore than 5.4kHzHI-Speed Dubbing Mode- 2-2 -3. RECORD BIAS ADJUSTMENTHeadUnitPN202GNDRecord/PlaybackheadTest TapeMTT-5511Record/Playbackand Pause ModeFrequency CounterDeck ModeTest TapeTest PointAdjustmentAdjust forRec/PauseMTT-5511ERASE HEADL20360kHz5kHz (Auto stop)WIRE(PN202)85kHz5kHz(Auto Reverse)Figure 3. Record Bias Adjustment Connection Diagram4. TUNER ADJUSTMENTFigure 4. Tuner(S curve) Adjustment Connection DiagramUnitSignal GeneratorGNDElectronicOSCILLOSCOPEFM AntennaTerminalSpeakerItemTest PointAdjustmentAdjust forDC VoltageChecker IC Pin 26, 28L1060V50mV(FM)- 2-3 -TROUBLESHOOTINGTurn power on.Is power on?Does initial read work?Does it play?Does it output audio?Check power supply circuit.PN807 PIN5, 6.2VPN807 PIN7, 5VIC803 PIN 2, 3.3VCheck the connectorPN801, PN802, PN809Check the tracking servo circuit.Check the PN807 PIN1, 3OKYESYESYESYESYESYESNONONOCheck the DISK turnsCheck the LaserCheck the focus circuitCheck the TRAKING circuitNONO- 2-4 -Fails to initial read AB2V5V0V5V0V1V0V1.2V0V0.8VNONONONONONONONONONOYESYESYESYESYESYESYESYESYESYESYESYESDisc motor turnsDoes RF waveform appear?IC801 Pin3Check the Data transmission fromPN809 pin11 to CD DSPCheck the Data transmission fromPN809 pin13 to MICOMCheck the change of SLDOVoltage(IC801 pin23)Check the change of SL +,SL - Voltage(IC802 pin 18, 19)Check the Voltage change of PN 809PIN20(OPEN, CLOSE)Defective connectorPN809Defective connectorPN809, DefectiveMICOMDefective connectorPN809, DefectiveIC801Defective IC801Defective IC802Defective contact PN802Defective PICK-UPDoes laser light?focus coil drive wareform.TRACKING ERROR wareformIs rotation normal?Defective IC801Defective PICK-UPIs there no dropout of RF signal?Does FA+ waveform appear atIC802 pin13?Does TE waveform appear at 801 pin 15?- 2-5 -NONONONONONOLaser does not light.Is “3.5V” applied to pin of IC 801?Is power supplied to laser Q801?(Q 801 collector: about 1.8V)Does laser current flow?1.0V across R808Is data transferred fromMICOM IC ?Does voltage appear at IC802 pin 17, 18?Defective MICOM.Defective MICOM.Defective connector.Defective IC 801, 802 Defective slide motor and/orconnector.Defective LMT SW and/orconnector.Defective Q 801 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 2 ofPN802?R8081.0VR8081.0VYESYESYESYESOPENCLOSEYESYESYESYESYESYES70- 2-6 -BNONONONONOYESYESYESYESLaser lightsDoes lens move up/down?Check the signal ofFOCUS SEARCH(IC801 Pin 21)Chekc the signal of PN802pin 13, 14Does FE signal appear?(IC801 pin 13)Does DRF signal appear? (IC 801 pin67)Defective IC801Defective IC802Open activator and/or connectorDefective IC801Degraded laser diodeDefective PICK-UP- 2-7 -(CH1)(CH2)1. HF signal (RF signal ) waveform(IC801 pin 3) during normal play 2. EFM signal (IC801 pin 3)waveformduring Normal Play3. Focus coil drive waveform(IC802 pin13) When focus search failed or there is no disc on the tray Focus coil drive waveform(FDO: IC801 pin21) andDRF(IC801 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 802 pin18)During normal playCH1 : FOCUS COIL DRIVESIGNAL 2V/Div.CH2 : DRFCH1 : TRACKING COIL DRIVESIGNAL 2V/Div. (IC802 pin27)CH2 : TRACKING ERROR(TE: IC801 pin15)1V/Div.(CH2 : TRACKING COIL DRIVE (IC802 pin27)SIGNAL 2V/Div.CH2 : TRACKING ERROR (TE: IC801 pin15)1V/Div.(CH1 : TRACKING COIL DRIVE (IC802 pin27)CH2 : TRACKING ERROR (TE: IC801 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)OVOVOVOVOVOVOVOVOVWAVEFORMS OF MAJOR CHECK POINT- 2-8 -VKK PARTDoes DC - 33V appear at CN302 Pin .Check the Voltage of IC301 PIN .Dose -33V appear at ZD704(-) Check the Q715 TURN ONCheck the PATTERNReplace the Q715Refer to power circuitENDCheck the -33V(LOW)of C704Replace the ZD704(-33V)Replace the D714,D718, D715YESYESNONOP-SENS PART Does +5V appear at ZD701?Check the pattern of IC301 Pin .Check the waveform of D713(Cathod).Check the 5.6K of R714 andreplace ZD703(5.1V)Replace the D713YESYESNONO142851- 2-9 -Power Circuit Check the Fuse Check the DC output C736Check the DC Output of C738Check the output of IC703, IC782, IC783Check the 5V of CN513 Pin 7 (CD FUNCTION)ENDReplace the Fuse Check the AC output of CN701 Pin4, 5Check the AC Output ofCN701 PIN 1, 3Replace the IC782Replace the D745, D746,D747, D748Check the D741, D742, D744, D734 or Replace.Check the IC703, IC782,IC783 or Replace.Check the Q713 “B”:HIGH,Q711 “B”:LOWCheck the High ofQ713 “B” or ReplaceCheck the IC301 or ReplaceReplace the Q713, Q711Check the power Assy orReplace the TransformerCheck the power Assy orReplace the TransformerCheck the 5V of IC301PIN 17,46,72,90Check the High of IC301 Pin 3.YESYESYESYESYESYESYESYESYESYESNONONONONONONONONONO- 2-10 -Audio abnormalCheck the output of IC701 Pin 26, 27Refer to “IC701Troubleshooting”Refer to “MutingTroubleshooting”Check the “High” of IC702 Pin 5. Check the Voltage of IC702 Pin 7. Check the power circuit.Check the input of IC702 P