LG-FFH1850-cs-sch 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 SPECIFICATIONS.1- 5 SECTION 2. ELECTRICAL ADJUSTMENTS.2- 1 TROUBLESHOOTING.2- 3 WAVEFORMS OF MAJOR CHECK POINT.2- 8 BLOCK DIAGRAM.2- 9 SCHEMATIC DIAGRAMS.2- 11 WIRING DIAGRAM.2- 19 PRINTED CIRCUIT DIAGRAMS.2- 21 INT

2、ERNAL BLOCK DIAGRAM OF ICs.2- 30 SECTION 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- 7 SECTION 4. SPEAKER.4-1 SECTION 5. REPLACEMENT PARTS LIST.5-1 RadioFans.CN 收音机爱 好者资料库 SECTIO

3、N 1. GENERAL SERVICING PRECAUTIONS NOTES REGARDING HANDLING OF THE PICK-UP 1. 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. 2. Repair notes 1) The p

4、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 and impact. If it is subjected to strong pressure or impact, the result may be an operational mal

5、function and/or damage to the printed- circuit 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 p

6、ermit 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 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

7、 is held by a delicate spring. When cleaning 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 not use an

8、y other liquid cleaners, because they will damage the lens.) Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick- up. - 1- 2 - Storage in conductive bagDrop impact NEVER look directly at the laser beam, and dont let contact fingers or other

9、exposed skin. Magnet How to hold the pick- up Pressure Pressure Cotton swab Conductive Sheet RadioFans.CN 收音机爱 好者资料库 NOTES REGARDING COMPACT DISC PLAYER REPAIRS 1. Preparations 1) Compact disc players incorporate a great many ICs as well as the pick- up (laser diode). These components are sensitive

10、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 optical components and other high- precision components. Care must be taken, therefor

11、e, to avoid repair or storage where the temperature of humidity is high, where strong magnetism is present, or where there is excessive dust. 2. Notes for repair 1) Before replacing a component part, first disconnect the power supply lead wire from the unit 2) All equipment, measuring instruments an

12、d 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 is the possibility of damage by static electricity.) 4) To prevent AC leakage, the

13、 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 static electricity changes in the clothing to escape from the armband. 7) The laser be

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

15、lume 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. - 1- 3 -

16、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) devices can be damaged easily by static electricity. Such components commonly are

17、 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 help reduce the incidence of component damage caused by static electricity. 1. I

18、mmediately 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 available discharging wrist strap device, which should be removed for potential

19、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 electrostatic charge buildup or exposure of the assembly. 3. Use only a grounded- tip solderi

20、ng 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. 5. Do not use freon- propelled chemicals. These can generate electrical charges s

21、ufficient 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 electrically shorted together by conductive foam, aluminum foil or comparable conductive

22、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. CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OT

23、HER 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 carpeted floor can generate static electricity sufficient to damage an ESD device). C

24、AUTION. GRAPHIC SYMBOLS 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 SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK. THE EXCLAMATION POINT WITHIN AN

25、 EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. - 1- 4 - SPECIFICATIONS 1. AMP SECTION 1) Power Output (6 , 2 channel, T.H.D. 10%).20W+20W 2) T.H.D.0.15% 3) Frequency Response (- 3dB down).42Hz25kHz 4) Signal- to

26、- noise Ratio.80dB 5) Input Sensitivity AUX.40050mV 6) Channel Difference 1kHz.2dB 2. TUNER SECTION 1) FM 1) Frequency Range.87.5MHz108MHz 2) Intermediate Frequency.10.7MHz 3) Sensitivity (90/98/106MHz).12dB 4) Signal- to- noise Ratio 98.1MHz(Mono/Stereo).64dB/55dB 5) Image Rejection 106.1MHz.18dB 6

27、) IF Rejection 90.1MHz.60dB 7) Distortion 98.1MHz(Mono/Stereo).1.2/1.2% 8) Frequency Response (- 3dB).60Hz10kHz 9) Stereo Separation (100Hz/1kHz/10kHz).25dB 2) AM(MW) 1) Frequency Range.522kHz1611kHz 2) Intermediate Frequency.455kHz 3) Usable Sensitivity.55dB/m 4) Image Rejection (1404kHz).20dB 5) I

28、F Rejection (603kHz).40dB 6) Selectivity (1008kHz).23dB 7) Signal- to- noise Ratio (1008kHz).35dB 8) Distortion (1008kHz).1.5% 9) Frequency Response (1008kHz).100Hz1800Hz 3) SW(OPTIONAL) 1) Frequency Range.5.8MHz18MHz 2) Intermediate Frequency.450kHz 3) Usable Sensitivity.40dB/m 4) Signal To Noise R

29、atio.35dB 5) Distortion . 3% 4) LW(OPTIONAL) 1) Frequency Range.153kHz281kHz 2) Intermediate Frequency.450kHz 3) Usable Sensitivity.65dB 4) Signal To Noise Ratio (200kHz).28dB 5) Distortion (200kHz).3% - 1- 5 - 3. TAPE DECK SECTION 1) Tape Speed (MTT- 111) / Normal Speed.4.75cm/sec 2) Wow Flutter (MTT- 111) .0.25% 3) Fast Forward and Rewind Time (C- 60).120sec 4) Frequency Response (6dB range).250Hz8kHz 5) Signal- to- noise Ratio (Playback/Record).43dB/43dB 6) Distortion (Playback/Record).3% / 4% 7) Crosstalk (Playback: