LG-LXU250A-cs-sm 维修电路原理图.pdf

《LG-LXU250A-cs-sm 维修电路原理图.pdf》由会员分享，可在线阅读，更多相关《LG-LXU250A-cs-sm 维修电路原理图.pdf（55页珍藏版）》请在收音机爱好者资料库上搜索。

1、MICRO COMPONENT SYSTEMSERVICE MANUALMODEL: LX-U250A, LXS-U250SERVICE MANUAL MODEL: LX-U250A, LXS-U250RadioFans.CN 收音机爱 好者资料库- 1-1 -CONTENTS SECTION 1. GENERAL SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ESD PRECAUTIONS . . .

2、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5 SECTION 2. ELECTRICAL TROUBLESHOOTING GUIDE . . . . . . . . . . .

3、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 WAVEFORMS OF MAKOR CHECK POINT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

4、BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33 WIRING DIAGRAM . . . . . . . . . . . . . . . . .

5、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-45 PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-47 SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . .

6、. . . . . . . . . . . . . . .3-1 SINGLE DECK MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3 CD MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5 SECTION 4. SPEAK

7、ER SECTION MODEL: LXS-U250, LXS-W250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 SECTION 5. REPLACEMENT PARTS LIST REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1RadioFans.C

8、N 收音机爱 好者资料库- 1-2 - SERVICING PRECAUTIONS NOTES 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 p

9、ick-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 malfunc

10、tion 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

11、 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 del

12、icate spring. When cleaning the lens 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 cleaner

13、s, 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.Storage in conductive bagDrop impactNEVER look directly at the laser beam, and dont let contact fingers or other exposed skin.MagnetHow to hold the

14、pick-upConductive SheetCotton swabPressurePressureSECTION 1. GENERAL- 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

15、. If such static electricity is high voltage, componentscan 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

16、 of humidity is high, where strong magnet-ism 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 c

17、overed 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) Wor

18、kers 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 NEVER be directly facing the eyes

19、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 ofthe volume knob for more than 3 seconds.If you reset your unit, you must

20、 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)ConductiveSheetResistor(1 Mohm)ArmbandRESET jump wireVOLUMEVOLUM

21、E KNOBDOWNUP- 1-4 - ESD PRECAUTIONS Electrostatically 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

22、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 electrostat

23、ic 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

24、 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 anti-static solder removal device. Some solder removal devices n

25、ot 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 yo

26、u areready to 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 ma

27、terial 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 ALLOTHER SAFETY PRECAUTIONS.8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motionsuch as the

28、 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 SYMBOLSTHE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TOALERT THE SERVICE PERSONN

29、EL TO THE PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” THATMAY 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-SONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.- 1-5

30、 - SPECIFICATIONSNOTE : Specification are subject to change without notice in the course of product improvement.- 1-6 - 2-1 -CD PART TROUBLESHOOTING GUIDESECTION 2. ELECTRICALTURN ON CDOPEN CLOSE CHECK“ READING ”DISPLAY CHECKREADING OK CHECKIF PLAY, AUDIO OUTPUT CHECKOKCONNECTOR CHECK (PN806)CHECK L

31、C78690W (IC801)CHECK AM5810FP (IC802) CHECK PICKUP MOVEMENT CONNECTOR CHECK(PN801,PN802)CHECK MICOM INTERFACE CIRCUIT( PN805 )CONNECTOR CHECK ( PN802, PN804, PN806 )CHECK MICOM INTERFACE CIRCUIT( PN805 )CHECK POWER SUPPLY CIRCUIT( PN806 )CONNECTOR CHECK ( PN804, PN806 )- 2-2 -OPEN CLOSE NGCONNECTOR

32、LOCKING CHECK ( PN804 )CHECK POWER SUPPLY CIRCUIT( PN805, PN806)PN 806 PIN 4 = 12V, PIN 5 = 6.2VPN805 PIN 1 = 5VCHECK VOLTAGE CHANGE OF OPEN CLOSE ,AND IC802 INPUT VOLTAGE PIN 7, 8, 20 (=6.2V)(PN805 PIN 2:BTL_MUTE, 14:OPEN 15:CLOSE)DEFECTIVE MAINPOEWR SUPPLYDEFECTIVE MICOMDEFECTIVEMECHANISM- 2-3 -“

33、READING ” DISPLAY CHECK(= ONLY “CD “DISPLAY)CONNECTOR LOCKING CHECK (PN802,PN804,PN805,PN806 )DEFECTIVE CONNECTOR ORMAIN POWER SUPPLAYDEFECTIVE IC804DEFECTIVE MICOM ORCONNECTORDEFECTIVE MICOM ORCONNECTORDEFECTIVE IC801CHECK VOLTAGE THE PIN 2 OF IC804IC804 PIN 2 :3.3VCHECK RESET SIGNAL OF PN805PN805

34、PIN 4 :3VCHECK POWER SUPPLYPORT( PN805 ,PN806)PN 806 PIN 4 = 12V, PIN 5 = 6.2VPN805 PIN 12 = 5VCHECK MICOM INTERFACECIRCUIT( PN805 )PN805 PIN 3,4,5,6,7,8,9 SIGNAL CHECK(3:WRQ, 4 :RESET 5 :DO, 6:DI, 7 :CL8:CE, 9:FSEQ)CHECK THE WAVE FORM #1- 2-4 -READING OK CHECK(= “NO DISC” DISPLAY)CONNECTOR LOCKINGC

35、HECK(PN801,PN802)DOES SLED MOVE ?DOES LENSE MOVE ?(= UP & DOWN)CHECK PN802 PIN 3,4( SL+,SL-)ABCDECHECK PN801 PIN 13,16( FA-, FA+)CHECK PN801 PIN 10( LD )CHECK PN802 PIN5,6( SP+,SP-)CHECK PN801 PIN 14,15 (TA-, TA+)DEFECTIVE PICKUP ORIC802 OR IC801DEFECTIVE PICKUP ORIC801DEFECTIVE PICKUP ORIC802 OR IC

36、801DEFECTIVE PICKUP ORIC802 OR IC801DEFECTIVE PICKUP ORIC802OR IC801DOES LASER LIGHT ?DOES SPINDLE ROTATE ?IS READING OK ?- 2-5 -READING OK CHECK #A(= “NO DISC” DISPLAY)ADOES SL+ WAVEFORM APPEARAT( IC802 PIN 13 AND PN 802 PIN 3)WAVEFORM #2SLED MOTOR WAVEDOES SLIN WAVEFORMAPPEAR AT( IC802 PIN 5)WAVEF

37、ORM #2SLED DRIVE WAVECHECK PN802 CONNECTOR LINEDEFECTIVE IC801DEFECTIVE IC802DEFECTIVE PN802CONNECTORDEFECTIVE PICKUPSLED MOTOR- 2-6 -READING OK CHECK #B(= “NO DISC” DISPLAY)BDOES FA+ WAVEFORM APPEAR AT( IC802 PIN 16 AND PN801 PIN 13)WAVEFORM #3FOCUS COIL DRIVE WAVEDOES FAIN- WAVEFORMAPPEAR AT( IC80

38、2 PIN 25)WAVEFORM #3FOCUS DRIVE WAVECHECK PN801 CONNECTOR LINEDEFECTIVE IC801DEFECTIVE IC802DEFECTIVE PN801CONNECTORDEFECTIVE PICKUPFOCUS ACTUATOR- 2-7 -READING OK CHECK #C(= “NO DISC” DISPLAY)CIS ?V APPLIED TO PIN10 OFPN501LASER SUPPLY VOLTAGE CHECKCHECK PN801 CONNECTOR LINEIS 3.3 V APPLIED TOPIN30

39、,36,39,41,61,68,75OF IC801RF IC SUPPLY VOLTAGECHECKIS 2.3 V PIN18 OF IC801LASER CONTROLVOLTAGE CHECKDEFECTIVE IC804DEFECTIVE IC801DEFECTIVE Q801 ORD801DEFECTIVE PN801CONNECTORDEFECTIVE PICKUPLASER PART- 2-8 -READING OK CHECK #D(= “NO DISC” DISPLAY)DDOES SP+ WAVEFORM APPEARAT( IC802 PIN 11 AND PN802

40、PIN 5)WAVEFORM #4SPINDLE MOTOR DRIVE WAVEDOES SPIN WAVEFORMAPPEAR AT( IC802 PIN 6)WAVEFORM #4SPINDLE DRIVE WAVECHECK PN802 CONNECTOR LINEDEFECTIVE IC801DEFECTIVE IC802DEFECTIVE PICKUPSPINDLE MOTORDEFECTIVE PN802CONNECTOR- 2-9 -READING OK CHECK #E(= “NO DISC” DISPLAY)EDOES TA+ WAVEFORM APPEAR AT( IC8

41、02 PIN 17 AND PN801 PIN 14)WAVEFORM #5TRACKING COIL DRIVE WAVECHECK PN802 CONNECTOR LINEDEFECTIVE IC801DEFECTIVE IC802DEFECTIVE PN802CONNECTORDEFECTIVE PICKUP ORIC801DEFECTIVE PICKUP ORIC801DOES ARF SIGNAL APPEAR?(IC801 PIN 2 )WAVEFORM #6DOES FE, TE SIGNAL APPEAR?(IC801 PORT FE:10, TE:16)WAVEFORM #6

42、DOES TAIN- WAVEFORMAPPEAR AT( IC802 PIN 22)WAVEFORM #5TRACKING DRIVE WAVE- 2-10 -#1. MICOM INTERFACE WAVEFORM(PN805 PIN 3, 4, 5, 6) during power onPIN 6 : DIPIN 5 : DOPIN 4 : RESETPIN 3 : WRQ#1. MICOM INTERFACE WAVEFORM(PN805 PIN 3, 4, 5, 6) during normal playPIN 6 : DIPIN 5 : DOPIN 4 : RESETPIN 3 :

43、 WRQ#1. MICOM INTERFACE WAVEFORM(PN805 PIN 7, 8, 9) during power onPIN 9 : FSEQPIN 8 : CEPIN 7 : CL#1. MICOM INTERFACE WAVEFORM(PN805 PIN 7, 8, 9) during normal playPIN 9 : FSEQPIN 8 : CEPIN 7 : CL WAVEFORMS OF MAKOR CHECK POINT- 2-11 -#2. SLED DRIVE AND MOTOR WAVEFORM(IC802 PIN 5, 13) when focus se

44、arch#3. FOCUS DRIVE AND MOTOR WAVEFORM #3. FOCUS DRIVE AND MOTOR WAVEFORM(IC802 PIN 25, IC802 PIN 16) (IC802 PIN 25, IC802 PIN 16) When focus search failed or there is no disc on trayThere is disc on tray and focus search successPIN 5 : SLINPIN 13 : SL+PIN 25 : FAOPIN 16 : FA+#2. SLED DRIVE AND MOTO

45、R WAVEFORM(IC802 PIN 5, 13) during normal playPIN 5 : SLINPIN 13 : SL+PIN 25 : FAOPIN 16 : FA+- 2-12 -#5. TRACK DRIVE AND MOTOR WAVEFORM(IC802 PIN 22 , IC802 PIN 17) during normal play#4. SPINDLE DRIVE AND MOTOR WAVEFORM(IC802 PIN 6, 11) when TOC readingPIN 6 : SPINPIN 11 : SP+PIN 22 : TAOPIN 17 : T

46、A+#6. RF, FOCUS AND TRACKING ERROR WAVEFORM(IC801 PIN 2, 10, 16) during normal playPIN 2 : RFOUTPIN 10 : FEPIN 16 : TE- 2-13 -USB PARTTURN ON USB“CHECKING ”OR“USB”DISPLAYCHECKREADING OK CHECKOKCONNECTOR CHECK ( PN805, PN806, PN810 )CHECK POWER SUPPLY CIRCUIT( PN806 )CHECK MICOM INTERFACE CIRCUIT( PN

47、805 )CHECK PN810 1 PIN :5VCHECK PN810 PIN 2(D-), 3(D+)CHECK OTI6888 (IC805)CHECK LC78690W (IC801)CONNECTOR CHECK (PN806)IF PLAY, AUDIOOUTPUT CHECK- 2-14 -VKK CHECKP-SENS CHECKPN301 3Pin DC -27V CHECKOKZD900 (+)VOLTAGE CHECK (5V)IC301 26PIN PATTERN CHECKZD901 (-)-27V CHECKD912(+)WAVE CHECKD912 CHANGE

48、YESYESNONOYESQ900 TURN ON CHECKC921(-)-27V UNDER VOLT CHECKYESNOD907,D906 CHANGEOKVOLTAGE CHECK LISTYESNOQ900 CHANGEYESNO- 2-15 -VOLTAGE CHECKALL Fuse CHECKIC901,IC902 INPUT DC VOLT CHECKC904(+),C905(-)DC VOLT OUTPUT CHECKD700 CHANGETransformerCHANGEIC301 Troubleshooting CHECKMUTEYESFUSE CHANGECN900

49、 (-)1,2 PIN,(+)5,6 PIN OUTPUT VOLTAGE,D900 CHECKYESNOYESNONOIC903 Output DC VOLT CHECK (6.2V)D901,D902,D903,D904 COMPONENT CHECK AND CHANGETransformer CHANGEYESCN901 7 Pin DC VOLTOUTPUT CHECKYESNONOIC903 Output DC VOLT CHECK (6.2V)D908 +12V CHECK AND CHANGEIC901 CHANGEYESD909,D910 VOLT CHECKYESYESNO

50、NOSECTION CHECKYESNOIC904 CHANGEQ500 CHECK AND CHANGEYESIC904 1PIN (+)High CHECKNONOMuting CIRCUIT Troubleshooting (MUTE CONDITION)Q201,Q251,Q600,Q650 Base HighIC201Troubleshooting CHECK (ONLY Q201/Q251)YESNOQ504 EMITTER HIGH(ONLY Q714/Q715)NOQ201,Q251,Q600,Q650 Collector LowMUTETR CHANGEYESNOQ504 C