LG-LMD2540A-cs-sm 维修电路原理图.pdf

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1、- 1-1 -CONTENTS SECTION 1.GENERAL SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SECTION 2.ELECTRICAL

2、 SECTION TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11 SCHEMATIC DIAGRAMS . . . . . . . . . . . . .

3、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13 WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27 PRINTED CIRCUIT BOARD DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4、. . . . . . . 2-29 SECTION 3.DVD PART DVD ELECTRICAL TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7 SCHEMATIC DIAGRAM . . . . . . . . . . . .

5、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27 PRINTED CIRCUIT BOARD DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33 SECTION 4. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . .

6、. . . . . . . . . . . . . . . . 4-1 TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK) . . . . . . . . . . . . . . . . . . . . . . . . .4-7 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 al

8、ways 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 cor

9、rectly 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, an

10、d 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 t

11、he 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, a cottonswab should be used, taking care not to distort this.6) Never attempt to d

12、isassemble 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

13、 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 swabPressurePressureRadioFans.CN 收音机爱 好者资料库- 1-3 -NOTES REGARDING COMPACT DISC PLAYER REPAIRS1. Preparations1

14、) 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, componentscan be damaged, and for that reason components should be handled with care.2) T

15、he 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 present, or where there is excessive dust.2. Notes for repair1) Before replacing a com

16、ponent 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 ba

17、g. (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

18、 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 unit to initial status if malfunction occur(button malfunction, display, etc.).Usin

19、g 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: 1.To operate the RESET jump wire, pull the volume rotary knob and release it.2.

20、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 Sensitive Devices (ESD)Some semiconductor (solid state) devices can be damaged eas

21、ily 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 c

22、omponent 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

23、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 exposure of the

24、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.The

25、se 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 foam, aluminu

26、m 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 O

27、R 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 sufficient

28、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 SHOCK.THE EXCL

29、AMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THESERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICELITERATURE.- 1-6 - 2-1 -SECTION 2. ELECTRICALVKK CHECKP-SENS CHECKPN903 PIN5, CN302 PIN5 DC -33V checkIC301 PIN51 DC -33V checkZD900 voltage check (+5.1V)I

30、C301 PIN26 checkZD901(+) -33V checkD901(+) waveform checkD901 replacementR902 check ZD900 replacementQ902 TURN ON checkC919(-) -33Vup to checkD908, D909 replacementTroubleshooting checkQ902 replacementnormal TROUBLESHOOTING GUIDEYESYESNONONOYESYESYESYESNONONO- 2-2 -POWER CHECKEvery kinds of Fuse che

31、ckIC700 “12”(+VH2), 6(-VH2) PIN DC power output checkFuse replacementPN900 PIN1, 5 DC voltage output checkD900 PIN2, 3 AC check replacementOKD900 replacementTransformer replacementCN901 PIN5 +12V(D) power checkCN901 PIN6, 7 DC +16V over power checkD901 AC voltage input checkTransformer replacementIC

32、902(7812) assemble check replacementYESYESYESYESYESYESNONONONONONONOCN901 PIN3 +6.2V(D) power checkD913 AC voltage input checkIC902(7812) assemble check replacementTransformer replacementCN901 PIN6, 7 DC +16V up to power checkCN901 PIN5 +12V(D) power checkIC901(7805) assemble check replacementYESYES

33、YESNONONONOCN901 PIN4 +12V(A) power checkCN901 PIN6, 7 DC +16V over power checkD901 AC voltage input checkIC301 PIN76 PWR-CTRL “HIGH” checkPATTERN checkTransformer replacementIC301 replacementCN901 PIN8 PWR - CTRL “HIGH” checkIC903(78R12) assemble check replacementYESYESYESYESNONONONONO- 2-3 -CN901

34、PIN11 +8V(A) power checkTransformer replacementCD/DVD/KARAOKE FUNCTION CN901 PIN9 PIN DVDCTRL “HIGH” checkPATTERN CheckIC301 PIN81 DVD-CTRL “HIGH”checkIC301 “81”+16 PIN DC +16 over power checkIC301replacementYESYESNONOCN901 PIN5 +12V(D) power checkIC904(78R08) check replacementD913 AC voltage input

35、checkIC902(7812) assemblecheckreplacementTransformer replacementCN901 PIN12 +5V power checkIC901 PIN10 DC +8V over power checkIC905(78R05) power checkD902/D903 AC power input checkYESYESYESYESNONONONONOCN901 PIN14 +3.3V power checkOKCN901 PIN10 DC +8V over power checkIC907(7805)/IC906(78R33) power c

36、heckD902/D903 AC power input checkTransformer replacementYESYESNO- 2-4 -Muting circuit Troubleshooting (if MUTE)IC301 PIN91 F-MUTE “HIGH” checkQ791 “C” PORT “HIGH” checkQ700/Q750 “C” PORT SIGNAL checkIC301 PIN2 WOOFER-MUTE “HIGH” checkQ741 “C” PORT “HIGH” checkQ740 “C” PORT signal checkQ740 replacem

37、entQ700/Q750 replacementMuting mode check IC301 replacementQ791 “E” PORT “HIGH” checkQ791 replacementnormalnormalMuting mode check IC301 replacementQ741 “E” PORT HIGH checkQ741 replacementPATTERN checkPATTERN checkYESYESYESYESYESYESYESNONONONONONO- 2-5 -Q700/750 “C” signal checkJK700 SPEAKER output

38、checkOKIC602 input checkQ795 “E” HIGH checkRY700 +12V(A) power checkRY700 replacementIC601 input checkIC602 replacementIC601 replacementIC605 replacementQ1725 TURN-ON checkSpeaker short checkOKQ1720 “B”(+), (-) DC voltage checkIC700 replacement+12V(A) power Troubleshooting referIC605 input checkeach

39、 function TROU-BLESHOOTING referno soundYESYESYESYESYESYESYESYESYESNONONONONONONONO- 2-6 -AUX FUNCTION SPEAKER outputTAPE FUNCTION SPEAKER outputIC700 output check(Front -L/R)Output sound Troubleshooting referIC601 PIN5, 24 input check(AUX -L/R)IC601 replacementIC602 PIN2, 9 input check (FRONT -L/R)

40、IC602 replacementOKOKIC700 input check (Front -L/R)IC602 PIN2, 19 input check(FRONT -L/R)IC700 replacementIC602 replacementJK600 AUX input signal cable or external component sound output check IC601 PIN4, 25 input check (IN -L/R)IC605 PIN4, 11 input checkIC202 PIN5, 20 output check(TAPE -L/R)IC605 r

41、eplacementIC601 replacementIC601 PIN5, 24 input check(IN-L/R)IC601 replacementSpecific FUNCTION MODE has no soundYESYESYESYESYESYESYESYESYESYESNONONONONONONONO- 2-7 -CD/DVD function speaker outputOKIC602 PIN2, 19:F-L/R, 3, 17PIN :R-L/R, PIN18:CNT input check IC602 replacementIC601 replacementIC601 P

42、IN3, 26 input check (DVD -L/R)PN600 PIN2, 4, 8, 10, 12 output check (DVD F-L/R, R-L/R, CNT)PATTERN checkDVD Troubleshooting referTUNER FUNCTION SPEAKER outputOKIC602 PIN2, 19 input check (FRONT -L/R)IC602 replacementIC601 replacementTUN100 PIN2 VCC +9V checkTUN100 PLL -CE/CLK/DI/DO ter-minal DATA co

43、rrespondence checkIC601 PIN4, 25 input check (FRONT -L/R)IC605 PIN3, 5 input check(TUNER -L/R)Pattern checkPower +12V(A) checkYESYESYESYESYESYESYESYESYESNONONONONONONONONO- 2-8 -IC301 U-COM IC TroubleshootingIC301 pin17, 46, 72, 90 +5V power checkIC301 PIN26 5V check (POWER-SENS)X301 oscilates or no

44、tWhen IC301 pin11 voltage input LowHighIC301 replacementCN302 PIN6 DC +5.6V checkPATTERN checkTroubleshooting Refer P-SENS referX301 replacementRESET circuit checkYESYESYESYESYESNONONONONOIC501(EXPENDER IC) TroubleshootingIC501 PIN16 +5V power checkIC501 PIN2, 3 pin CLK Data checkCONTROLL function c

45、hecknormalTroubleshooting Refer IC301 TROUBLESHOOTING referIC301, IC501 pattern checkIC301 PIN3, 4 Data check (CD, TAPE FUNCTION change)IC501(BU2090F) replacementYESYESYESYESNONONONO- 2-9 -IC700(AMP IC) TroubleshootingPIN10, 14 Signal input check2(+VH2), 1(-VH2) power checkPIN3, 4, 5, 6 signal outpu

46、t checkOKMuting circuit referPIN3, 4, 5, 6 DC checkPower IC replacementPower IC replacementYESYESYESYESNONOTAPE PLAYIC202 “18”pin VCC checkIC202 “5, 20”pin signal output checkMuting circuit checkTroubleshooting check referDeck Mecha operation checkIC202 replaementDeck Mecha replaementYESYESYESNONONO

47、- 2-10 -IC501 Troubleshooting referTAPE REC check (A252, Q202 On: R273, R223 HighIC202 PIN11, 14 signal input checkIC202 PIN9, 16 output checkIC201 6”(12V) , PIN4 High checkL203 PIN5, 6 oscilates or notDECK replaementQ253, Q203 Base “Low” checkQ253, Q203 replaementIC202 PIN18 VCC checkIC501 Troubles

48、hooting checkC236(+) power input checkTroubleshooting check referIC501 Troubleshooting checkQ208 replaementL203 replaementQ208 Base 0.6V checkQ208 Collector LowQ207 replaementnormalYESYESYESYESYESYESYESYESYESNONONONONONONONONODubbing check (“NORMAL”or “HIGH”) checkQ252, 202 “OFF”/”ON”:R273, 223 “LOW

49、”/ “HIGH”Q253, 203 “OFF”/”ON”:R225, 275 “LOW”/ “HIGH”IC501 Troubleshooting checkREC check referYESYESNO BLOCK DIAGRAM2-112-122-132-14 SCHEMATIC DIAGRAMS MAIN SCHEMATIC DIAGRAM2-152-16 MAIN(AMP), SUB POWER SCHEMATIC DIAGRAM2-172-18 MAIN(DECK) SCHEMATIC DIAGRAM2-192-20 FRONT SCHEMATIC DIAGRAM2-212-22

50、MIC SCHEMATIC DIAGRAM2-232-24 POWER, A/V JACK SCHEMATIC DIAGRAM2-252-26 POWER, A/V JACK SCHEMATIC DIAGRAM2-272-28 WIRING DIAGRAM2-292-30 PRINTED CIRCUIT DIAGRAMS MAIN P.C. BOARD (SOLDER SIDE)2-312-32 MAIN P.C. BOARD (COMPONENT SIDE) 2-332-34 FRONT P.C. BOARD (SOLDER SIDE)2-352-36 FRONT P.C. BOARD (C