Panasonic-SCTM22-cs-sm 电路图 维修手册.pdf
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1、SA-TM22SB-TM22SB-TM22 MODELO : SC-TM22 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? RadioFans.CN 收音机爱 好者资料库 1 Safety Precaution (This “Safety Precaution” is applied only in U.S.A.) Before servicing, unplug the power cord to prevent an electric shock. When replacing parts, use only manufacturers recommended
2、 components for safety. Check the condition of the power cord. Replace if wear or damage is evident. After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc. Before returning the serviced equipment to the customer, be sure to make the following insula
3、tion resistance test to prevent the customer from being exposed to a shock hazard. 1.1 Insulation Resistance Test Unplug the power cord and short the two prongs of the plug with a jumper wire. Turn on the power switch. Measure the resistance value with ohmmeter between the jumper AC plug and each ex
4、posed metal cabinet part, such as screwheads, antenna, control shafts, handle brackets, etc.Measure the resistance value with ohmmeter between the jumper AC plugand each exposed metal cabinet part, such as screwheads, antenna, control shafts, handle brackets, etc. Equipment with antenna terminals sh
5、ould read between 2.7M and 3.9M to all exposed parts*. ( Fig.1 ) Equipment without antenna terminals should read approximately infinity to all exposed parts. ( Fig.2 ) *Note : Some exposed parts may be isolated from the chassisby design. These will read infinity. If the measurement is outside the sp
6、ecified limits, there is a possibility of a shock hazard. The equipment should be repaired and re-checked before it is returned to the customer. Fig.1 Fig.2 RadioFans.CN 收音机爱 好者资料库 2 Before Repair and Adjustment Disconnect AC power, discharge Power Supply Capacitors C520 and C540 through a 10, 5W re
7、sistor to ground. DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices. After repairs are completed, restore power gradually using a variac, to avoid overcurrent. Current consumption at AC 120V, 60 Hz in NO SIGNAL mode (volume min at CD mode
8、) should be 600mA. 3 Protection Circuitry The protection circuitry may have operated if either of the following conditions are noticed: No sound is heard when the power is turned on. Sound stops during a performance. The function of this circuitry is to prevent circuitry damage if, for example, the
9、positive and negative speaker connection wires are “shorted”, or if speaker systems with an impedance less than the indicated rated impedance of the amplifier are used. If this occurs, follow the procedure outlines below: Turn off the power. Determine the cause of the problem and correct it. Turn on
10、 the power once again after one minute. Note : When the protection circuitry functions, the unit will not operate unless the power is first turned off and then on again. 4 Prevention of Electro Static Discharge (ESD) to Electrostatically Sensitive (ES) Devices Some semiconductor (solid state) device
11、s can be damaged easily by electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistorsand semiconductor “chip” components. The following techniques should be used to help reduce th
12、e incidence of component damage caused by electro static discharge (ESD). Immediately before handling any semiconductor component or semiconductor-equiped assembly, drain off any ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ES
13、D wrist strap, whichshould be removed for potential shock reasons prior to applying power to the unit under test. After removing an electrical assembly equiped with ES devices, place the assembly on a conductive surface such as aluminium foil, to prevent electrostatic charge build up or exposure of
14、the assembly. Use only a grounded-tip soldering iron to solder or unsolder ES devices. Use only an anti-static solder remover device. Some solder removal devices not classified as “anti-static (ESD protected)” can generate electrical charge to damage ES devices. Do not use freon-propelled chemicals.
15、 These can generate electrical charges sufficient to damage ES devices. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, alumi
16、nium foil orcomparable conductive material). Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed. RadioFans.CN 收音机爱 好者资料库 Caution Be sure no power is ap
17、plied to the chassis or circuit, and observe all other safety precautions. Minimize body motions when handling unpackaged replacement ES 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 elec
18、tricity (ESD) sufficient todamage an ES device). 5 Handling the Lead-free Solder 5.1 About lead free solder (PbF) Distinction of PbF P.C.B.: P.C.B.s (manufactured) using lead free solder will have a PbF stamp on the P.C.B. Caution: Pb free solder has a higher melting point than standard solder; Typi
19、cally the melting point is 50 - 70F (30 - 40C) higher. Please use a high temperature soldering iron. In case of soldering iron with temperature control,please set it to 700 20F (370 10C). Pb free solder will tend to splash when heated too high (about 1100F/600C). When soldering or unsoldering, pleas
20、e completely remove all of the solder on the pins or solder area, and be sure to heat the soldering points with the Pb free solder until it melts enough. 6 Handling Precautions For Traverse Deck The laser diode in the traverse deck (optical pickup) may break down due to potential difference caused b
21、y static electricity of clothes or human body. So, be careful of electrostatic breakdown during repair of the traverse deck (optical pickup). Handling of traverse deck (optical pickup) Do not subject the traverse deck (optical pickup) to static electricity as it is extremely sensitive to electrical
22、shock. The short land between the No.4(LD) and No.5(GND) pins on the flexible board (FFC) is shorted with a solder build-up to prevent damage to the laser diode.To connect to the PC board, be sure to open by removing the solder build-up, and finishthe workquickly. Take care not to apply excessive st
23、ress to the flexible board (FFC). Do not turn the variable resistor (laser power adjustment). It has already been adjusted. Fig 6.1 Grounding for electrostatic breakdown prevention Human body grounding Use the anti-static wrist strap to discharge the static electricity from your body. Work table gro
24、unding Put a conductive material (sheet) or steel sheet on the area where the traverse deck (optical pickup) is placed, and ground the sheet. Caution : The static electricity of your clothes will not be grounded through the wrist strap. So, take care not to let your clothes touch the traverse deck (
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