Panasonic AW-CB400L Service Manual

Also see for AW-CB400L: Operating instructions

Contents

Panasonic AW-CB400L Service Manual Manual pdf 4 page image

- - 4 -SAFETY PRECAUTIONSGENERAL GUIDELINES1. When servicing, observe the original lead dress. If a shortcircuit is found, replace all parts which have beenover-heated or damaged by the short circuit.2. After servicing, see to it that all the protective devicessuch as insulation barriers, insulation papers shields areproperly installed.3. After servicing, make the following leakage currentchecks to prevent the customer from being exposed toshock hazards.LEAKAGE CURRENT COLD CHECK1. Unplug the AC cord and connect a jumper between thetwo prongs on the plug.2. Measure the resistance value, with an ohm meter,between the jumpered AC plug and each exposedmetallic cabinet part on the equipment such asscrewheads, connectors, control shafts, etc. Theresistance value must be more than 5MΩ.Figure1LEAKAGE CURRENT HOT CHECK (See Figure 1)1. Plug the AC cord directly into the AC outlet.Do not use an isolation transformer for this check.2. Connect a 1.5KΩ, 10W resistor, in parallel with a 0.15μ Fcapacitor, between each exposed metallic part on the setan a good earth ground such as a water pipe, as shown inFigure1.3. Use an AC voltmeter, with 1000 ohms/volt or moresensitivity, to measure the potential across the resistor.4. Check each exposed metallic part, and measure thevoltage at each point.5. Reverse the AC plug in the AC outlet repeat each of theabove measurements.6. The potential at any point should not exceed 0.15 voltsRMS. A leakage current tester (Simpson Model 229equivalent) may be used to make the hot checks, leakagecurrent must not exceed 0.1 milliamp. In case ameasurement is outside of the limits specified, there is apossibility of a shock hazard, and the equipment shouldbe repaired and rechecked before it is returned to thecustomer.ABOUT LEAD FREE SOLDER (PbF)Distinction of Pbf PCB:PCBs (manufactured) using lead free solder will have a PbFstamp on the PCB.Caution:1. Pb free solder has a higher melting point than standardsolder; Typically the melting point is 50–70 (30-40 )higher. Please use a high temperature soldering iron. Incase of the soldering iron with temperature control,please set it to 700±20 (370±10 ).2. Pb free solder will tend to splash when heated too high(about 1100 /600 ).ELECTROSTATICALLY SENSITIVE (ES) DEVICESSome semiconductor (solid state) devices can be damagedeasily by static electricity. Such components commonly arecalled Electrostatically sensitive (ED) Devices. Examples oftypical ES devices are integrated circuits and somefield-effect transistors and semiconductor “chip” components.The following techniques should be used to help reduce theincidence of component damage caused by static electricity.1. Immediately before handling any semiconductorcomponent or semiconductor-equipped assembly, drainoff any electrostatic charge on your body by touching aknown earth ground.Alternatively, obtain and wear a commercially availabledischarging wrist trap device, which should be removedfor potential shock reasons prior to applying power to theunit under test.2. After removing an electrical assembly equipped with ESdevices, place the assembly on a conductive surfacesuch as alminum foil, to prevent electrostatic chargebuildup or exposure of the assembly.3. Use only a grounded tip soldering iron to solder orunsolder ES devices.4. Use only an anti-static solder removal device classified as“anti-static” can generate electrical charges sufficient todamage ES devices.5. Do not use freon-propelled chemicals. These cangenerate electrical charges sufficient to damage ESdevices.6. Do not remove a replacement ES device from itsprotective package until immediately before you are readyto install it.(most replacement ES devices are package with leadselectrically shorted together by conductive foam, alminumfoil or comparable conductive material).7. Immediately before removing the protective material fromthe leads of a replacement ES device, touch theprotective material to the chassis or circuit assembly intowhich the device will be installed.CAUTION : Be sure no power is applied to the chassis orcircuit, and observe all other safety precautions.8. Minimize bodily motions when handling unpackagedreplacement ES devices. (Otherwise hamless motionsuch as the brushing together of your clothes fabric or thelifting of your foot from a carpeted floor can generatestatic electricity sufficient to damage an ES device).X-RADIATIONWARNING1. The potential source of X-radiation in EVF sets is theHigh Voltage section and the picture tube.2. When using a picture tube test jig for service, ensure thatjig is capable of handling 10kV without causingX-Radiation.Note : It is important to use an accurate periodicallycalibrated high voltage meter.3. Measure the High Voltage. The meter (electric type)reading should indicate 2.5kV,±0.15kV. If the meterindication is out of tolerance, immediate service andcorrection is required to prevent the possibility ofpremature component failure. To prevent an X-Radiationpossibility, it is essential to use the specified picture tube.