LG-FFH976-cs-sp 维修电路原理图.pdf
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1、- 1-2 -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.2. Repair notes1) T
2、he 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 mal
3、function 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 l
4、aser 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
5、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. (Donot use any other liquid cl
6、eaners, 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 letcontact fingers or other exposed skin.MagnetHow to hold
7、the pick-upaPressurePressureCotton swabConductive SheetRadioFans.CN 收音机爱 好者资料库- 1-3 -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 easily affected by, static
8、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 avoid repair or storage where the
9、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 be grounded.3) The workbench sh
10、ould 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 ground
11、ed.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 should NEVER be directly facing the
12、 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 seconds. If you reset your unit, y
13、ou 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.ArmbandConductiveSheetResistor(1 Mohm)Resistor(1 Mohm)VOLUME KNOBUPDOWNV
14、OLUMERESET jump wireRadioFans.CN 收音机爱 好者资料库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 i
15、ntegratedcircuits 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, d
16、rain 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 ass
17、embly 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 removal device. Some sol
18、der 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
19、 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,
20、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 devices. (Otherwise harm
21、less 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).- 1-4 - 1-5 -SPECIFICATIONS1. AMP SECTION1) Power Output (6 , 2 channel, T.H.D. 10%) .30W+30W 120W+120W2) T.H.D 0.2% .0
22、.2% 1.0%3) Frequency Response (-3dB down) .700Hz25kHz 45Hz700Hz4) Signal-to-noise Ratio .85dB 75dB5) Input Sensitivity AUX .40050mV 40050mV6) Channel Difference 1kHz .2dB-2. TUNER SECTION1) FM/OIRT1) Frequency Range . 87.5MHz108MHzor 65.0MHz74.0MHz & 87.5MHz108MHz2) Intermediate Frequency. 10.7MHz3)
23、 Sensitivity (70MHz/78.6MHz/83.0MHz/86.6MHz/90MHz/98MHz). 12dB4) Signal-to-noise Ratio 98.1MHz(Mono/Stereo). 61dB/58dB5) Image Rejection 106.1MHz. 20dB6) IF Rejection 90.1MHz . 65dB7) Distortion 98.1MHz(Mono/Stereo). 1.2/1.2%8) Frequency Response (-3dB) . 60Hz10kHz9) Stereo Separation (100Hz/1kHz/10
24、kHz). 23dB2) AM(MW)1) Frequency Range . 522kHz1611kHz/530kHz1610kHz/530kHz1720kHz2) Intermediate Frequency. 450kHz3) Usable Sensitivity. 55dB4) Image Rejection (1404kHz) . 25dB5) IF Rejection (603kHz). 40dB6) Selectivity (1008kHz). 23dB7) Signal-to-noise Ratio (1008kHz). 35dB8) Distortion (1008kHz)
25、. 1.5%9) Frequency Response (1008kHz). 100Hz1800Hz3) SW(OPTIONAL)1) Frequency Range. 5.8MHz18MHz2) Intermediate Frequency. 450kHz3) Usable Sensitivity. 40dB4) Signal To Noise Ratio. 35dB5) Distortion . 3%4) LW(OPTIONAL)1) Frequency Range . 153kHz281kHz2) Intermediate Frequency. 450kHz3) Usable Sensi
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