LG-LM230-cs-sm 维修电路原理图.pdf
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1、- 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 INTER
2、NAL 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-
3、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.
4、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
5、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!Ab
6、solutely 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 len
7、s). 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. (Dono
8、t 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 oth
9、er exposed skin.MagnetHow to hold the pick- upPressurePressureCotton swabConductive SheetRadioFans.CN 收音机爱 好者资料库NOTES 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
10、 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 avoi
11、d 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 b
12、e 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
13、 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 s
14、hould 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
15、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
16、(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 typica
17、l 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-
18、 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 remov
19、ing 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 r
20、emoval 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
21、 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
22、 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
23、 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 TRIAN
24、GLE, 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 SAFET
25、Y INFORMATION IN SERVICELITERATURE.- 1- 4 - 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 ha
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