LG-LFSU850-cs-sm 维修电路原理图.pdf

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1、MICRO HI-FI SYSTEMSERVICE MANUALMODEL: LF-U850D, LF-U850A,LFS-U850SERVICE MANUAL MODEL: LF-U850D, LF-U850A, LFS-U850CAUTIONBEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL.RadioFans.CN 收音机爱 好者资料库- 1-1 -CONTENTS SECTION 1.GENERAL SERVICING PRECAUTIONS . . . . . . . . . . . . .

2、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3、. . . . . . . . . . . . . . . .1-5 SECTION 2.ELECTRICAL SECTION TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-

4、6 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14 CD PART . . . . . . . . . . . . . . . . . . . .

5、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20 WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26 PRINTED CIRCUIT BOARD DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . .

6、. . . . . . . . . . . . . 2-28 SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Deck Mechanism Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 SECTION 4

7、. SPEAKER PART MODEL:LFS-U850 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 SECTION 5. REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1RadioFans.CN 收音机爱 好者资料库- 1-2 -SECTION 1. GENERAL SERVICING PREC

8、AUTIONSNOTES 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

9、, 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-ci

10、rcuit 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

11、 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 len

12、s surface, therefore, a cottonswab 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 len

13、s.) Take care not to use too much ofthis alcohol on the swab, and do not allow the alcohol to get inside the pick-up.Storage 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 swabP

14、ressurePressure- 1-3 -NOTES REGARDING COMPACT DISC PLAYER REPAIRS1. Preparations1) Compact disc players incorporate a great many 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, componen

15、tscan 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 must betaken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong magnet-ism is prese

16、nt, 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 remov

17、ing 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 sho

18、uld be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent sta-tic 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 un

19、it 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 ofthe volume knob for more than 3 seconds.If you reset your unit, you must reenter all its settings(stations, clock, timer)NOTE:

20、 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.Resistor(1 Mohm)ConductiveSheetResistor(1 Mohm)ArmbandRESET jump wireVOLUMEVOLUME KNOBDOWNUP- 1-4 - ESD PRECAUTIONSElectrostatically S

21、ensitive 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 co

22、mponents.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

23、. 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 conductive sur-face s

24、uch 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 cha

25、rges 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 areready to install it. (Most replacement ESD devices

26、 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 th

27、e device will by installed.CAUTION : BE SURE NO POWER IS APPLIED TO THE 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 liftin

28、g of your foot from a carpeted floor can gen-erate 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 “DAN-GEROUS VOLTAGE” T

29、HAT 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.- 1-5 - SPECIFICATIONSMODELLF-U850D/ASECTIONPower supplyRefer t

30、o the back panel of the unit.Power consumption50 WMass3.7 kgBattery Operation187 X 255 X 257 mmFrequency response40 - 18000 HzSignal-to-noise ratio70 dBDynamic range70 dBTuning Range87.5 - 108.0 MHz or 65 - 74 MHz, 87.5 - 108.0 MHzIntermediate Frequency10.7 MHzSignal to Noise Ratio60/55 dBFrequency

31、Response60 - 10000 HzTuning Range522 - 1620 kHz or 520 - 1720 kHzIntermediate Frequency450 kHzSignal to Noise Ratio34 dBFrequency Response120 - 2000 HzOutput Power80 W + 80 WT.H.D0.5 %Frequency Response42 - 20000 HzSignal-to-noise ratio75 dBTypeBass Reflex 3Way 4SpeakerImpedance6 Frequency Response6

32、0 - 20000 HzSound Pressure Level82 dB/W (1m)Rated Input Power80 WMax. Input Power160 WNet Dimensions (WxHxD)162x320 x258 mmNet Weight (1EA)4.0 kgGeneralCDAmpSpeakersTUNERAM (MW)FM* Designs and specifications are subject to change without notice.- 2-1 -SECTION 2. ELECTRICAL SECTIONP-SENS PART CHECKSM

33、PS ASSY CN943 - 4PIN 5V OPERATION CHECKMAIN PCB PN101 4PIN 5V CHECKMAIN PCB PN304 27PIN 5V CHECKREFER TO SMPS TROUBLESHOOTING TROUBLESHOOTING GUIDEYESYESNOPN101 CONTACT STATUS CHECKMAIN PCB PATTERN disconnection checkNOFRONT CN304 7PIN 5V CHECKYESFRONT IC302 OPERATION AND INPUT VOLTAGE 4.7V5.0V CHEC

34、KYESYESU-COM 26PIN 5V CHECKYESIC302 INPUT VOLTAGE 4.7V OR ABOVE , OUTPUT VOLTAGE3V OR ABOVE OPERATION CHECKIC304 KIA7042 REPLACEMENTNOYESVKK CHECKCN943 6PIN DC -33V CHECKMAIN PCB PN101 6PIN VOLTAGE -33V CHECKREFER TO SMPS TROUBLESHOOTINGYESYESNOMAIN PCB PATTERN DISCONNECTION CHECKNOPN304 3PIN VOLTAG

35、E CHECK (-33V)YESFFC WIRE ASSEMBLY STATUS CHECKNOFRONT PCB CN304 3PIN VOLTAGE CHECK (-33V)IC301 51PIN VOLTAGE CHECKYESFRONT PCB PATTERN DISCONNECTION CHECKNO- 2-2 -U-COM 5V VOLTAGE CHECK SMPS ASSY CN943 - 3PIN 5V OPERATION CHECK MAIN PCB PN101 3PIN 5VCHECKREFER TO SMPS TROUBLESHOOTINGYESNOMAIN PCB P

36、N304 5PIN 5.6VCHECKPN101 CONTACT STATUS CHECKYESMAIN PCB PATTERN DISCONNECTION CHECKYESNOFRONT CN304 29PIN 5.6V CHECKFFC WIRE ASSEMBLY STATUS CHECKYESNOU-COM 17,46,72,90PIN 4.7V5V CHECKFRONT PCB PATTERN DISCONNECTION CHECKYESNOQ303 (A103S) BASE HIGH CHECKQ301, Q302,Q502,Q503(D1304S) BASE HIGH CHECKC

37、-COM 10PIN (HIGH) OPERATION STATUS CHECKYESIC603(CS5340) 10PIN,12PIN INPUT CHECKIC603(CS5340) 2PIN (MCLK), 4PIN (SDOUT), 7PIN(SCLK), 8PIN (LRCK) OUTPUT WAVEFORM CHECKYESQ303(A103S)OPERATION STATUS CHECKYESREPLACE Q303(A103S) IF FAULTYYESMUTEYESNOREPLACE EACH APPROPRIATE TRNOC-COM 10PIN LINE CHECK AN

38、D U-COMREPLACEMENTNOMUTING CIRCUIT TROUBLESHOOTING (ON MUTE CONDITION)HEAD PHONE MUTE CHECK- 2-3 -FUNCTION INPUT UNFELT (IC601 BU4052)CD FUNCTION IC601 (BU4052)5,14PIN INPUT WAVEFORM CHECKNORMAL OPERATIONU-COM (IC301)83PIN,84PIN COMMUNICATION CHECK.MUTING MODE CHECK IC301 REPLACEMENTC601 (BU4052)16P

39、INVDD,8PIN VSS POWER CHECKREPLACE APPROPRIATE PARTSYESYESYESYESNORMALREPLACE APPROPRIATE PARTSYESYESNORMALNORMALIC602 (MC4580) 4PIN VSS,8PIN VDD POWER CHECK.REFER TO SMPSTROUBLESHOOTINGPN805 ASSEMBLY STATUS CHECKYESIC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECKYESNONOIC601 (BU4052)3,13PIN OUTPUT WAVEFOR

40、M CHECKYESNOYESFRONT CN304 MAIN PCB PN302 FFC WIRE contact and assembly status checkNOREPLACE FAULTY PARTS- 2-4 -AUX FUNCTION IC601 (BU4052)4,11PIN INPUT WAVEFORM CHECKNORMAL OPERATIONU-COM (IC301)83PIN,84PIN COMMUNICATION CHECK.MAIN PCB PATTERN DISCONNECTION CHECKIC601 (BU4052)16PINVDD,8PIN VSS POW

41、ERCHECKREPLACE APPROPRIATE PARTSYESYESYESYESNORMALREPLACE APPROPRIATE PARTSYESYESNORMALNORMALIC602 (MC4580) 4PIN VSS,8PIN VDD POWERCHECK.REFER TO SMPSTROUBLESHOOTINGJK601 CONTACT STATUS CHECKYESIC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECKYESNONOIC601 (BU4052)3,13PIN OUTPUT WAVEFORMCHECKYESNOYESFRONT C

42、N304 MAIN PCB PN302 FFC WIRE contact and assemblyNOREPLACE FAULTY PARTS- 2-5 -TUNER FUNCTION IC601 (BU4052)2,15PIN INPUT WAVEFORM CHECKNORMAL OPERATIONU-COM (IC301)83PIN,84PIN COMMUNICATIONCHECK.Refer to TUNER Troubleshooting and check power (2PIN12Vcheck)IC601 (BU4052)16PINVDD,8PIN VSS POWER CHECKR

43、EPLACE APPROPRIATE PARTSYESYESYESYESNORMALREPLACE APPROPRIATE PARTSYESYESNORMALNORMALIC602 (MC4580) 4PIN VSS,8PIN VDD POWERCHECK.REFER TO SMPSTROUBLESHOOTINGTUNER MODULE (TU601) OPERATION CHECKYESIC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECKYESNONOIC601 (BU4052)3,13PIN OUTPUT WAVEFORM CHECKYESNOYESFRON

44、T CN304 MAIN PCB PN302 FFC WIRE CONTACT AND ASSEMBLY STATUS CHECKNOREPLACE FAULTY PARTS- 2-6 - INTERNAL BLOCK DIAGRAM of ICs MSGEQ7BLOCK DIAGRAMOutputMultiplexor400HzBandpass1kHzBandpass2.5kHzBandpass6.25kHzBandpass16kHzBandpassPeakDetectorPeakDetectorPeakDetectorPeakDetectorPeakDetectorClockOscilla

45、torAnti-AliasFilterReset StrobeAudioInCKINDC OutPeakDetectorPeakDetector63HzBandpass160HzBandpass UTC MC4580PIN CONFIGURATION 12348765OUT2IN2(-)IN1(+)Vcc-Vcc+OUT 1IN1(-)IN2(+ )- 2-7 - PS9813BLOCK DIAGRAMSampleRateConverterInputMuxInputMixerDe-emphasisCross-overFilterPLLVolumeControlPWMModulatorAutom

46、aticGainLimiterInternal ClocksInternal Control(SUB) SLRCKSBCKSDINOSC_INPLL_EXT_LPFSCLSDAI2CInterfacePWM_CH1_PPWM_CH1_MPWM_CH2_PPWM_CH2_MPWM_CH3_PPWM_CH3_MOVERLOADNRESETSA(MAIN) MLRCKMBCKMDINEPD_ENA*3 or5BandEQDynamicBassBoostPWM_LOL_PPWM_LOL_MPWM_LOR_PPWM_LOR_MPWM_HP_LPWM_HP_RPIN ASSIGNMENT5VDDA CKI

47、NVSSA RESETOUT GNDSTROBE IN- 2-8 -PIN DESCRIPTIONSName Pin NO. Type Descri ption Power and Ground PLL_AVDD 2 Analog Power PLL analog power supply. 2.5V supply voltage. PLL_AVSS 5 Analog GroundPLL analog ground. PLL_DVDD 1 PLL Power PLL peripheral digital power supply. 2.5V supply voltage. PLL_DVSS 6

48、 PLL GroundPLL digital ground. PLL_AGS 4 PLL GroundPLL Analog Ground Sensing. VDD 11,38 Power 2.5V Digital power supply. Core power supply. VSS 12, 37 GroundCore digital ground. IO_VDD 13,27,46 Power 3.3V Digital power supply. I/O power supply. IO_VSS 12,20,30,45 GroundI/O digital ground. System Ser

49、vices /RESET 10 I H/W reset signal. Active Low Schmitt-Trigger input. The Schmitt-Trigger input allows a slowly rising input to reset the chip reliably. The RESET signal must be asserted Low during power up. De-assert High for normal operation. CLK_IN 48 I External clock input. 12.288MHz is recommen

50、ded. When the PLL_BYPASS is “LOW”, the external clock input from CLK_IN is used as PLL reference clock source. The external oscillator generates 12.288MHz clock and the internal PLL generates 98.304MHz (12.288MHz x 8) system clock. SA 7 I Slave Address Set for Host Interface PLL_EXT_LPF 3 Analog Ext