LG-LFSU850-cs-sm 电路图 维修手册.pdf

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1、MICRO HI-FI SYSTEM SERVICE MANUAL MODEL: LF-U850D, LF-U850A, LFS-U850 SERVICE MANUAL MODEL: LF-U850D, LF-U850A, LFS-U850 CAUTION BEFORE 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4、 . . . 2-6 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

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

8、RVICING PRECAUTIONS NOTES REGARDING HANDLING OF THE PICK-UP 1. Notes for transport and storage 1) 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 notes 1) The pick-up incorporat

9、es 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 and impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or dam

10、age to the printed-circuit board. 3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason the adjustment point and installation screws should absolutely never be touched. 4) Laser beams may damage the eyes! Absolutely never permit laser beams to

11、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 surface If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used for camera lens).The lens is held by a delicate

12、spring. When cleaning the lens surface, therefore, a cotton 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 not use any other liquid cleaners,

13、 because they will damage the lens.) Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up. Storage in conductive bagDrop impact NEVER look directly at the laser beam, and dont let contact fingers or other exposed skin. Magnet How to hold t

14、he pick-up Conductive Sheet Cotton swab Pressure Pressure RadioFans.CN 收音机爱 好者资料库 - 1-3 - NOTES REGARDING COMPACT DISC PLAYER REPAIRS 1. Preparations 1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode).These components are sensitive to, and easily affected by, s

15、tatic electricity. If such static electricity is high voltage, 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 must be taken, therefore, to avoid repair or storage w

16、here the temperature of humidity is high, where strong magnet- ism is present, or where there is excessive dust. 2. Notes for repair 1) Before replacing a component part, first disconnect the power supply lead wire from the unit 2) All equipment, measuring instruments and tools must be grounded. 3)

17、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 is because there is the possibility of damage by static electricity.) 4) To prevent AC leakage, the metal part of the soldering ir

18、on 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 changes in the clothing to escape from the armband. 7) The laser beam from the pick-up should NE

19、VER be directly facing the eyes or bare skin. CLEARING MALFUNCTION You 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 the volume knob for more than 3 seco

20、nds. 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. Resistor (1 Mohm) Conductive Sheet Resis

21、tor (1 Mohm) Armband RESET jump wire VOLUME VOLUME KNOB DOWN UP - 1-4 - ESD PRECAUTIONS Electrostatically Sensitive Devices (ESD) Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examp

22、les of typical ESD devices are integrated circuits and some field-effect transistors and semiconductor chip components.The following techniques should be used to help reduce the incidence of component damage caused by static electricity. 1. Immediately before handling any semiconductor component or

23、semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under tes

24、t. 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 exposure of the assembly. 3. Use only a grounded-tip soldering iron to solder or unsolder ESD devices. 4. Use only an

25、anti-static solder removal device. Some solder removal devices not classified as anti-static can generate electrical charges sufficient to damage ESD devices. 5. Do not use freon-propelled chemicals.These can generate electrical charges sufficient to damage ESD devices. 6. Do not remove a replacemen

26、t ESD device from its protective package until immediately before you are ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive materials). 7. Immediately before removing the protective mate

27、rial from the leads of a replacement ESD device, touch the protective 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 OTHER SAFETY PRECAUTIONS. 8. Minimize bodily motions when handin

28、g unpackaged replacement ESD devices. (Otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can gen- erate static electricity sufficient to damage an ESD device). CAUTION. GRAPHIC SYMBOLS THE LIGHTNING FLASH WITH APROWHEAD S

29、YMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DAN- GEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK. THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PER

30、SONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. - 1-5 - SPECIFICATIONS MODEL LF-U850D/A SECTION Power supplyRefer to the back panel of the unit. Power consumption50 W Mass3.7 kg Battery Operation187 X 255 X 257 mm Frequency response40 - 18000 Hz Signal-to-noise ratio70

31、dB Dynamic range70 dB Tuning Range87.5 - 108.0 MHz or 65 - 74 MHz, 87.5 - 108.0 MHz Intermediate Frequency10.7 MHz Signal to Noise Ratio60/55 dB Frequency Response60 - 10000 Hz Tuning Range522 - 1620 kHz or 520 - 1720 kHz Intermediate Frequency450 kHz Signal to Noise Ratio34 dB Frequency Response120

32、 - 2000 Hz Output Power80 W + 80 W T.H.D0.5 % Frequency Response42 - 20000 Hz Signal-to-noise ratio75 dB TypeBass Reflex 3Way 4Speaker Impedance6 Frequency Response60 - 20000 Hz Sound Pressure Level82 dB/W (1m) Rated Input Power80 W Max. Input Power160 W Net Dimensions (WxHxD)162x320 x258 mm Net Wei

33、ght (1EA)4.0 kg GeneralCDAmpSpeakers TUNER AM (MW)FM * Designs and specifications are subject to change without notice. - 2-1 - SECTION 2. ELECTRICAL SECTION P-SENS PART CHECK SMPS ASSY CN943 - 4PIN 5V OPERATION CHECK MAIN PCB PN101 4PIN 5V CHECK MAIN PCB PN304 27PIN 5V CHECK REFER TO SMPS TROUBLESH

34、OOTING TROUBLESHOOTING GUIDE YES YES NO PN101 CONTACT STATUS CHECK MAIN PCB PATTERN disconnection check NO FRONT CN304 7PIN 5V CHECK YES FRONT IC302 OPERATION AND INPUT VOLTAGE 4.7V5.0V CHECK YES YES U-COM 26PIN 5V CHECK YES IC302 INPUT VOLTAGE 4.7V OR ABOVE , OUTPUT VOLTAGE 3V OR ABOVE OPERATION CH

35、ECK IC304 KIA7042 REPLACEMENT NO YES VKK CHECK CN943 6PIN DC -33V CHECK MAIN PCB PN101 6PIN VOLTAGE -33V CHECK REFER TO SMPS TROUBLESHOOTING YES YES NO MAIN PCB PATTERN DISCONNECTION CHECK NO PN304 3PIN VOLTAGE CHECK (-33V) YES FFC WIRE ASSEMBLY STATUS CHECK NO FRONT PCB CN304 3PIN VOLTAGE CHECK (-3

36、3V) IC301 51PIN VOLTAGE CHECK YES FRONT PCB PATTERN DISCONNECTION CHECK NO - 2-2 - U-COM 5V VOLTAGE CHECK SMPS ASSY CN943 - 3PIN 5V OPERATION CHECK MAIN PCB PN101 3PIN 5VCHECK REFER TO SMPS TROUBLESHOOTING YES NO MAIN PCB PN304 5PIN 5.6VCHECK PN101 CONTACT STATUS CHECK YES MAIN PCB PATTERN DISCONNEC

37、TION CHECK YES NO FRONT CN304 29PIN 5.6V CHECK FFC WIRE ASSEMBLY STATUS CHECK YES NO U-COM 17,46,72,90PIN 4.7V5V CHECK FRONT PCB PATTERN DISCONNECTION CHECK YES NO Q303 (A103S) BASE HIGH CHECK Q301, Q302,Q502,Q503(D1304S) BASE HIGH CHECK C-COM 10PIN (HIGH) OPERATION STATUS CHECK YES IC603(CS5340) 10

38、PIN,12PIN INPUT CHECK IC603(CS5340) 2PIN (MCLK), 4PIN (SDOUT), 7PIN (SCLK), 8PIN (LRCK) OUTPUT WAVEFORM CHECK YES Q303(A103S)OPERATION STATUS CHECK YES REPLACE Q303(A103S) IF FAULTY YES MUTE YES NO REPLACE EACH APPROPRIATE TR NO C-COM 10PIN LINE CHECK AND U-COM REPLACEMENT NO MUTING CIRCUIT TROUBLES

39、HOOTING (ON MUTE CONDITION) HEAD PHONE MUTE CHECK - 2-3 - FUNCTION INPUT UNFELT (IC601 BU4052) CD FUNCTION IC601 (BU4052)5,14PIN INPUT WAVEFORM CHECK NORMAL OPERATION U-COM (IC301)83PIN,84PIN COMMUNICATION CHECK. MUTING MODE CHECK IC301 REPLACEMENT C601 (BU4052)16PINVDD,8PIN VSS POWER CHECK REPLACE

40、APPROPRIATE PARTS YES YES YES YES NORMAL REPLACE APPROPRIATE PARTS YES YES NORMAL NORMAL IC602 (MC4580) 4PIN VSS,8PIN VDD POWER CHECK. REFER TO SMPS TROUBLESHOOTING PN805 ASSEMBLY STATUS CHECK YES IC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECK YES NO NO IC601 (BU4052)3,13PIN OUTPUT WAVEFORM CHECK YES NO

41、 YES FRONT CN304 MAIN PCB PN302 FFC WIRE contact and assembly status check NO REPLACE FAULTY PARTS - 2-4 - AUX FUNCTION IC601 (BU4052)4,11PIN INPUT WAVEFORM CHECK NORMAL OPERATION U-COM (IC301)83PIN,84PIN COMMUNICATION CHECK. MAIN PCB PATTERN DISCONNECTION CHECK IC601 (BU4052)16PINVDD,8PIN VSS POWER

42、 CHECK REPLACE APPROPRIATE PARTS YES YES YES YES NORMAL REPLACE APPROPRIATE PARTS YES YES NORMAL NORMAL IC602 (MC4580) 4PIN VSS,8PIN VDD POWER CHECK. REFER TO SMPS TROUBLESHOOTING JK601 CONTACT STATUS CHECK YES IC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECK YES NO NO IC601 (BU4052)3,13PIN OUTPUT WAVEFOR

43、M CHECK YES NO YES FRONT CN304 MAIN PCB PN302 FFC WIRE contact and assembly NO REPLACE FAULTY PARTS - 2-5 - TUNER FUNCTION IC601 (BU4052)2,15PIN INPUT WAVEFORM CHECK NORMAL OPERATION U-COM (IC301)83PIN,84PIN COMMUNICATION CHECK. Refer to TUNER Troubleshooting and check power (2PIN12Vcheck) IC601 (BU

44、4052)16PINVDD,8PIN VSS POWER CHECK REPLACE APPROPRIATE PARTS YES YES YES YES NORMAL REPLACE APPROPRIATE PARTS YES YES NORMAL NORMAL IC602 (MC4580) 4PIN VSS,8PIN VDD POWER CHECK. REFER TO SMPS TROUBLESHOOTING TUNER MODULE (TU601) OPERATION CHECK YES IC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECK YES NO N

45、O IC601 (BU4052)3,13PIN OUTPUT WAVEFORM CHECK YES NO YES FRONT CN304 MAIN PCB PN302 FFC WIRE CONTACT AND ASSEMBLY STATUS CHECK NO REPLACE FAULTY PARTS - 2-6 - INTERNAL BLOCK DIAGRAM of ICs MSGEQ7 BLOCK DIAGRAM Output Multiplexor 400Hz Bandpass 1kHz Bandpass 2.5kHz Bandpass 6.25kHz Bandpass 16kHz Ban

46、dpass Peak Detector Peak Detector Peak Detector Peak Detector Peak DetectorClock Oscillator Anti-Alias Filter Reset Strobe Audio In CKIN DC Out Peak Detector Peak Detector 63Hz Bandpass 160Hz Bandpass UTC MC4580 PIN CONFIGURATION 1 2 3 4 8 7 6 5 OUT2 IN2(-)IN1(+) Vcc- Vcc+OUT 1 IN1(-) IN2(+ ) - 2-7

47、- PS9813 BLOCK DIAGRAM Sample Rate Converter Input Mux Input Mixer De- emph asis Cross- over Filter PLL Volume Control PWM Modulator Automatic Gain Limiter Internal Clocks Internal Control (SUB) SLRCK SBCK SDIN OSC_INPLL_EXT_LPF SCL SDA I2C Interface PWM_CH1_P PWM_CH1_M PWM_CH2_P PWM_CH2_M PWM_CH3_P

48、 PWM_CH3_M OVERLOAD NRESET SA (MAIN) MLRCK MBCK MDIN EPD_ENA *3 or 5 Band EQ Dynamic Bass Boost PWM_LOL_P PWM_LOL_M PWM_LOR_P PWM_LOR_M PWM_HP_L PWM_HP_R PIN ASSIGNMENT 5 VDDA CKIN VSSA RESET OUT GND STROBE IN - 2-8 - PIN DESCRIPTIONS Name Pin NO. Type Descri ption Power and Ground PLL_AVDD 2 Analog

49、 Power PLL analog power supply. 2.5V supply voltage. PLL_AVSS 5 Analog Ground PLL analog ground. PLL_DVDD 1 PLL Power PLL peripheral digital power supply. 2.5V supply voltage. PLL_DVSS 6 PLL Ground PLL digital ground. PLL_AGS 4 PLL Ground PLL 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 Services /RESET 10 I H/W reset sig