LG-LX220-cs-sm 电路图 维修手册.pdf

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1、- 1- 1 - CONTENTS SECTION 1. GENERAL SERVICING PRECAUTIONS.1- 2 ESD PRECAUTIONS.1- 4 SPECIFICATION.1- 5 SECTION 2. TROUBLESHOOTING ADJUSTMENTS.2- 1 TROUBLESHOOTING . 2- 3 WAVEFORMS OF MAJOR CHECK POINT. 2- 7 BLOCK DIAGRAM.2- 16 SCHEMATIC DIAGRAMS.2- 18 WIREING DIAGRAM. 2- 26 PRINTED CIRCUIT DIAGRAMS

2、. 2- 28 INTERNAL BLOCK DIAGRAM OF ICs . 2- 39 PRINTED CIRCUIT DIAGRAMS.2- 53 SECTION 3. EXPLODED VIEWS CABINET AND MAIN FRAME SECTION.3- 1 SECTION 4. SPEAKER SECTION SPEAKER SECTION. 4- 1 SECTION 5. REPLACEMENT PARTS LIST REPLACEMENT PARTS LIST.5- 1 RadioFans.CN 收音机爱 好者资料库 SERVICING PRECAUTIONS NOTE

3、S REGARDING HANDLING OF THE PICK-UP 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. Repair notes 1) The pick- up incorporates a strong magnet, and so

4、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 damage to the printed- circui

5、t 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 enter the eyes! Also NEV

6、ER 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 spring. When cleaning

7、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 - 1- 2 - Storage in conductive bagDrop impact NEVER loo

8、k directly at the laser beam, and dont let contact fingers or other exposed skin. Magnet How to hold the pick- up Pressure Pressure Cotton swab Conductive Sheet SECTION 1. GENERAL RadioFans.CN 收音机爱 好者资料库 NOTES REGARDING COMPACT DISC PLAYER REPAIRS Preparations 1) Compact disc players incorporate a g

9、reat many ICs as well as the pick- up (laser diode). These components are sensitive to, and easily affected by, static 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 o

10、ptical components and other high- precision components. Care must be taken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong magnetism is present, or where there is excessive dust. Notes for repair 1) Before replacing a component part, first disconnect th

11、e power supply lead wire from the unit 2) 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 is because there i

12、s 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 stat

13、ic 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 MALFUNCTION You can reset your unit to initial status if malfunction occur(button malfunction, display, etc.). Using a pointed good c

14、onductor(such as driver), simply short the RESET jump wire on the inside of the 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

15、 operate the RESET jump wire, it is necessary to unplug the power cord. - 1- 3 - Armband Conductive Sheet Resistor (1 Mohm) Resistor (1 Mohm) VOLUME KNOB UP DOWN VOLUME RESET jump wire RadioFans.CN 收音机爱 好者资料库 ESD PRECAUTIONS Electrostatically Sensitive Devices (ESD) Some semiconductor (solid state)

16、devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some field- effect transistors and semiconductor chip components. The following techniques should be used to

17、 help reduce the incidence of component damage caused by static electricity. 1. Immediately before handling any semiconductor component or semiconductor- equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially

18、 available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under test. 2. After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostati

19、c 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 can generate electrical charges sufficient to damage ESD devices.

20、5. Do not use freon- propelled chemicals. These can generate electrical charges sufficient to damage ESD devices. 6. Do not remove a replacement ESD device from its protective package until immediately before you are ready to install it. (Most replacement ESD devices are packaged with leads electric

21、ally shorted together by conductive foam, aluminum foil or comparable conductive materials). 7. Immediately before removing the protective material 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. CA

22、UTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER SAFETY PRECAUTIONS. 8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carp

23、eted floor can generate static electricity sufficient to damage an ESD device). CAUTION. GRAPHIC SYMBOLS - 1- 4 - THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED DANGEROUS VOLTAGE THAT MAY BE OF SUFF

24、ICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK. THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. - 2- 1 - TAPE DECK ADJUSTMENT 1. AZIMUTH ADJUSTMENT Figure 1. Azimuth Adjust

25、ment Connection Diagram CH1 CH2 Speaker Out Playback Mode Head Test Tape MTT- 114 L ch R ch GND Dual- trace synchroscope Electronic Voltmeter L out R out Unit 2. MOTOR SPEED ADJUSTMENT Head Unit PN202 GNDRecord/Playback head Test Tape MTT- 5511 Record/Playback and Pause Mode Frequency Counter Deck M

26、odeTest TapeTest TapeAdjustmentAdjust for Rec/PauseMTT- 5511 ERASE HEAD L201 60kHz5kHz (Auto stop) WIRE(PN201)85kHz5kHz(Auto Reverse) Figure 2. Motor Speed Adjustment Connection Diagram SECTION 2. ELECTRICAL SECTION ADJUSTMENTS This set has been aligned at the factory and normally will not require f

27、urther adjustment. As a result, it is not recommended that any attempt is made to modificate any circuit. If any parts are replaced or if anyone tampers with the adjustment, realignment may be necessary. IMPORTANT 1. Check Power- source voltage. 2. Set the function switch to band being aligned. 3. T

28、urn 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. Deck ModeTest TapeTest TapeAdjustmentAdjust for PalybackMTT- 114Speake

29、r Out DECK Screw Maximum Azimuth Screw - 2- 2 - 3. TUNER ADJUSTMENT Figure 3. Tuner(S curve) Adjustment Connection Diagram Unit Signal Generator GND Electronic OSCILLOSCOPE FM Antenna TerminalSpeaker ItemTest PointAdjustmentAdjust for DC VoltageCheck Point TP1, TP2L1010V50mV (FM) - 2- 3 - TROUBLESHO

30、OTING CD PART Turn power on. Is power on? Does initial read work? Does it play? Does it output audio? Check power supply circuit. PN508 PIN8, 6.2V PN508 PIN7, 5V IC503 PIN2, 3.3V Check the connector PN503, PN504, PN507 Check the tracking servo. Check the PN508 PIN1, 3 OK NO YES YES YES NO NO NO NO N

31、ONO Check the DISK circuit Check the Laser Check the focus circuit Check the TRAKING servo. NO NO - 2- 4 - FAILS TO INITIAL READ A B 2V 5V 0V 5V 0V 1V 0V 1.2V 0V 0.8V NONO NO NO NO NO NO NO YES YES YES YES YES YES YES YES YES YES YES YES Disc motor turns Does RF waveform appear? IC501 Pin3 Check the

32、 Data transferred from PN507 pin8 to CD DSP Check the Data transferred from PN507 pin6 to MICOM SLDO Voltage (IC501 pin23) Check the change of SL +, SL - Voltage (IC502 pin 18, 19) Check the Voltage change of PN 507 PIN2(OPEN, CLOSE) Defective connector PN507 Defective connector PN507, Defective MIC

33、OM Defective connector PN507, Defective IC501 Defective IC501 Defective IC502 Defective contact PN503 Defective PICK- UP Does laser light? focus coil drive wareform. TRACKING ERROR wareform Is rotation normal? Defective IC501 Defective PICK- UP Is there no dropout of RF signal? Does FA+ waveform app

34、ear at IC502 pin18? Does TE waveform appear at IC501 pin15? - 2- 5 - NO NO NO NO NO NO Laser does not light. Is 3.5V applied to pin80 of IC801? Is power supplied to laser Q501? (Q501 collector: about 1.8V) Does laser current flow? (R508s voltage are 1.0V) Is data transferred from MICOM IC ? Does vol

35、tage appear at IC 502 pin18, 19? Defective MICOM. Defective MICOM. Defective connector. Defective IC501, 502 Defective slide motor and/or connector. Defective LMT SW and/or connector. Defective Q 501 and/or laser. Defective laser and/or connector. Did pickup return to innermost circular? Does it sto

36、p at inner pick circular after shift? Is defect output from LM SW applied to pin 5 of PN503? R5081.0V R5081.0V YES YES YES YES OPENCLOSE YES YES YES YES YES YES - 2- 6 - B NO NO NO NO NO YES YES YES YES Laser lights Does lens move up/down? Check the signal of FOCUS SEARCH (IC501 Pin 21) Chekc the si

37、gnal of PN502 pin 13, 14 Does FE signal appear? (IC501 pin 13) Does DRF signal appear? (IC501 pin67) Defective IC501 Defective IC502 Open activator and/or connector Defective IC501 Degraded laser diode Defective PICK- UP - 2- 7 - (CH1) (CH2) WAVEFORMS OF MAJOR CHECK POINT 1. HF signal (RF signal ) w

38、aveform (IC501 pin4) during normal play 2. EFM signal (IC501 pin 3)waveform during Normal Play 3. Focus coil drive waveform(IC502 pin13) When focus search failed or there is no disc on the tray Focus coil drive waveform(FDO: IC501 pin21) and DRF(IC501 pin67) when focus search is accomplished 4. Trac

39、king coil drive waveform and TE during track traverse (1) When time division is 20mS/Div.1V/Div. (2) When time division 1mS/Div, 1V/Div (During forward track traverse) (3) When time division is 0.5nS/div. (During backward Track Traverse) 5. Feed motor drive waveform(IC 502 pin18) During normal play

40、CH1 : FOCUS COIL DRIVE SIGNAL 2V/Div. CH2 : DRF CH1 : TRACKING COIL DRIVE SIGNAL 2V/Div. (IC502 pin27) CH2 : TRACKING ERROR(TE: IC501 pin15) 1V/Div. ( ( ( CH1 : TRACKING COIL DRIVE (IC502 pin27) SIGNAL 2V/Div. CH2 : TRACKING ERROR (TE: IC501 pin15) 1V/Div. ( CH1 : TRACKING COIL DRIVE (IC502 pin27) C

41、H2 : TRACKING ERROR (TE: IC501 pin15) ( 0.5V/Div. 500nS/Div. (1S/Div. 1V/Div. (1mS/Div. 1V/Div. ( 0.5V/Div. 5S/Div. ( 2S/Div. 0.5V/Div. OV OV OV (CH1) (CH2) (CH1) (CH2) (CH2) OV OV OV OV OV OV OV OV OV - 2- 8 - VKK PART Does DC - 27V appear at PN303 Pin . OK Dose - 27V appear at ZD601(- ) Check the

42、TURN ON Replace the Q601 Refer to power circuit OK Check the - 27V(Lower) of C603(- ) Replace the D601, D602 YES YES NO NO P-SENS PART Does +5V appear at ZD702? Check the pattern of IC301 Pin . Check the waveform of D706(+). Check the R718 and replace ZD 702 Replace the D706 YES YES NO NO 26 20 - 2-

43、 9 - POWER CIRCUIT Check the Fuse Check the DC output of C715(+), C716(- ) Check the DC 12V Input of IC702 Check the DC 6.2V output of IC704 Check the DC 12V Output of IC703 Check the Collector (5.6V) of Q704 (CD FUNCTION) OK Replace the Fuse Check the power Replace the D701, D702, 703, 704 Check th

44、e Pattern of IC702 and IC704 Check the High of IC703 pin4 Replace the IC703 Refer to IC401 TROUBLESHOOTING Replace the Transformer Check the LOW of IC401 pin8 YES YES YES YES YES YES YES NO NO NO NO NO - 2- 10 - MUTE MUTING CIRCUIT (MUTE) Dose High appear at Q701, Q751 B check the LOW Q701, Q751, C Refer to IC203 Troubleshooting (ONLY Q201/Q251) Check the High of Q702 E Replace the TR Replace the Q702 Refer to IC301 Troubleshooting YES YES YES NO NO NO AUDIO ABNORMAL Check the output of IC701 Pin 2, 4 Check the speaker c