Zenith-LX140-cs-sm 维修电路原理图.pdf

MICRO COMPONENTRadioFans.CN 收音机爱 好者资料库- 1-1 -CONTENTS SECTION 1. GENERAL SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5 SECTION 2. ELECTRICAL ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 WAVEFORMS OF MAJOR CHECK POINT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21 SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23 WIREING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31 PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32 INTERNAL BLOCK DIAGRAM OF ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39 SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1 SECTION 4. SPEAKER SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 SECTION 5. REPLACEMENT PARTS LIST REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1RadioFans.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 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, 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-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 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 delicate 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 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.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 swabPressurePressure- 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, 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 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 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 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 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.).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: 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 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 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 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 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 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.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 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 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 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, ISINTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DANGER-OUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRICSHOCK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THESERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICELITERATURE.- 1-5 - SPECIFICATIONS- 1-6 -MEMO- 2-1 -SECTION 2. ELECTRICAL ADJUSTMENTSThis set has been aligned at the factory and normally will not require further adjustment. As a result, it isnot recommended that any attempt is made to modificate any circuit. If any parts are replaced or if any-one tampers with the adjustment, realignment may be necessary.IMPORTANT1. Check Power-source voltage.2. Set the function switch to band being aligned.3.Turn volume control to minimum unless otherwise noted.4. Connect low side of signal source and output indicator to chassis ground unless otherwise specified.5. Keep the signal input as low as possible to avoid AGC and AC action.TAPE DECK ADJUSTMENTCH1 CH2Speaker OutPlayback ModeHeadTest TapeMTT-114L chR chGNDDual-tracesynchroscopeElectronicVoltmeterL outR outUnit1. AZIMUTH ADJUSTMENT2.TUNER ADJUSTMENTFigure 1. Azimuth Adjustment Connection DiagramDeck Mode Test Tape Test Point Adjustment Adjust forPalyback MTT-114 Speaker Out DECK Screw Maximum Azimuth ScrewHeadPlayback ModeUnitSpeaker OutGNDL outR outRecord/PlaybackheadTest TapeMTT-111Frequency CounterFigure 1. Azimuth Adjustment Connection DiagramItem Test Point Adjustment Adjust forDC Voltage Check point TP1, TP2DECK Screw 0V 50mV- 2-2 - CD PART TROUBLESHOOTING- 2-3 - OPEN CLOSE NG- 2-4 - “ READING ” DISPLAY CHECK(= ONLY “CD “DISPLAY) - 2-5 - READING OK CHECK(= “NO DISC” DISPLAY)- 2-6 - READING OK CHECK #A(= “NO DISC” DISPLAY)- 2-7 - READING OK CHECK #B(= “NO DISC” DISPLAY)- 2-8 - READING OK CHECK #C(= “NO DISC” DISPLAY)- 2-9 - READING OK CHECK #D(= “NO DISC” DISPLAY)- 2-10 - READING OK CHECK # E(= “NO DISC” DISPLAY)- 2-11 - WAVEFORMS OF MAKOR CHECK POINT- 2-12 -#4. SPINDLE DRIVE AND MOTOR WAVEFORM(IC503 pin6, 1 2) when TOC reading#5. TRACK DRIVE AND MOTOR WAVEFORM(TP560, IC503 pin23) during normal play#6. RF, TRACKING AND FOCUS ERROR WAVEFORM(IC502 pin8, 2 1 , 23) during normal play- 2-13 - AUDIO PART- 2-14 - 2-15 - 2-16 - 2-17 -FM(TU101) TroubleshootingCheck the 12V input of TU101 pin6Check the “High” of TU101 Pin5Check the 12V of Q102 “E”Check the Power circuitRefer to “IC103Troubleshooting”Check the “LOW” of IC103 pin7Replace the Q102Replace the TU101Check the OSC waveform of TU101 pin8Refer to “IC102 Troubleshooting”YESYESYESYESYESNONONOIC102 TroubleshootingCheck the power input of IC102 pin8Check the wavefor of IC102 Pin20, 21Refer to “PowerTroubleshooting”Check the FM(TU101), AM(L102)Replace the IC102Check the “LOW” of IC102 Pin 13Replace the IC103Refer to “IC103Troubleshooting”Check the waveform output IC102 pin 16, 17ENDYESYESYESNONONO- 2-18 -IC103 TroubleshootingAM COIL TroubleshootingCheck the Power input of IC103 pin17X104 oscillationRefer to “PowerTroubleshooting”Repleace the X104Repleace the IC103Refer to “IC103 Troubleshooting”CE: Chip EnableDI: Data Input (from u-com)DO: Data Output (to u-com)CLK:Tuner mode clockCheck the Clock of CE, DI, DO, CLKCheck the operationENDYESYESYESYESNONONONOCheck the “High” of L102 Pin2Check the oscillation the L102 pin 13Check the IC102 TroubleshootingRefer to “IC103Troubleshooting”Replace the L102YESNO- 2-19 -PLAYCheck the B+ Power to LEAF SwitchChecks the B+ power to Q201 “E”Check the CN901 pin8, 9 and IC903 outputCheck the signal to IC202 pin4, 11Check the SW201 and HEAD connectorCheck the output tospeakerCheck the CN202Check the CN201YESYESYESYESNONONORECCheck the signal input of IC201 pin4, 11Check the of CN201 pin4, 5Check the oscillation of L201Check the signal input toPN201 pin8, 9Check the HEAD connectorCheck the B+ of LEAFswitchCheck the R218, L201, L204YESYESYESNONONO- 2-20 -MEMO BLOCK DIAGRAM2-212-222-232-24 SCHEMATIC DIAGRAMS FRONT/POWER SCHEMATIC DIAGRAM 2-252-26 MAIN/DECK SCHEMATIC DIAGRAM 2-272-28 TUNER SCHEMATIC DIAGRAM2-292-30 CDP SCHEMATIC DIAGRAM2-312-32 WIRING DIAGRAM2-332-34 PRINTED CIRCUIT DIAGRAMS FRONT P.C. BOARD2-352-36 MAIN P.C. BOARD2-372-38 CDP P.C. BOARD- 2-39 - INTERNAL BLOCK DIAGRAM OF ICsI IC300 LC87F73C8A1) Pin Assignment - 2-40 -I IC601 TDA7468D1) BLOCK DIAGRAM- 2-41 -2) PIN CONNECTION- 2-42 -I IC301 BU19231) BLOCK DIAGRAM?- 2-43 -I IC102LA18371) BLOCK DIAGRAMI IC102LA18372) Test Circuit Diagram- 2-44 -I IC103 LC72131D1) Pin Assignments- 2-45 -I IC201 AN73121) BLOCK DIAGRAMI IC701 LA46311) BLOCK DIAGRAM- 2-46 -I IC504 M12L16161A1) Synchronous DRAM PIN DefinitionsPINNAMEINPUT FUNCTIONCLKSystem ClockActive on the positive going edge to sample all inputs.CSChip Select Disables or enables device operation by masking or enabling allinputs except CLK, CKE and L(U)DQM.CKEClock EnableMasks system clock to freeze operation from the next clock cycle.CKE should be enabled at least one cycle prior to new command.Disable input buffers for power down in standby.A0A10/APAddressRow/column addresses are multiplexed on the same pins.Row address: RA0 RA10, column address : CA0CA7BABank Select AddressSelects bank to be activated during row address latch time.Selects bank for read/write durring column address latch time.RASRow Address Strobe Latches row addresses ont eh positive going edge of the CLKwith RAS low.CASColumn Address StrobeLatches column addresses on the positive going edge of the CLKwith CAS low.Enables column access.WEWrite EnableEnalbes write operation and row precharge.Latches data in starting form CAS, WE active.L(U)DQMData Input/Output MaskMakes data output Hi-z, tSHZ after the clock and masks the out-put. Blocks data input when L(U) DQM active.3-13-2 CABINET AND MAIN FRAME SECTIONSECTION 3. EXPLODED VIEWSA43450260261262A46282281A43305280451451451A46295294293291292290A00251254253250255256257258A40266266270252268267269NOTE) Refer to “SECTION 5 REPLACEMENTPARTS LIST” in order to look for the part number of each part.Caution pointA43: Front + Power Array Assembly.A46: Main + TP Deck + Tuner Array Assembly.- 4-1 -SECTION 4. SPEAKER SECTION MODEL: LXS-M140855854853852851861850850- 4-2 -MEMO