Panasonic AG-1980P Service Manual

Also see for ProLine AG-1980P: Operating instructions Service manual Operating instructions

SAFETY PRECAUTIONSGENERAL GUIDELINES1. When servicing, observe the original leaddress. If a short circuit is found, replace allparts which have been overheated or damaged bythe short circuit.2. After servicing, see to it that all theprotective devices such as insulation barriers,insulation papers shields are properlyinstalled.3. After servicing, make the following leakagecurrent checks to prevent the customer frombeing exposed to shock hazards.LEAKAGE CURRENT COLD CHECK1. Unplug the AC cord and connect a jumper betweenthe two prongs on the plug.2. Measure the resistance value, with an ohmmeter, between the jumpered AC plug and eachexposed metallic cabinet part on the equipmentsuch as screwheads connectors, controlshafts, etc. When the exposed metallic part has areturn path to the chassis, the readingshould be between 1M ohm and 5.2M ohm.When the exposed metal does not have a returnpath to the chassis, the reading must be oo.LEAKAGE CURRENT HOT CHECK (See Figure 1)1. Plug the AC cord directly into the AC outlet.Do not use an isolation transformer for thischeck.2. Connect a 1.5k ohm, 10 watts resistor, inparallel with a 0.1 5uF capacitor, between eachexposed metallic part on the set and a goodearth ground such as a water pipe, as shown inFigure 1.3. Use an AC voltmeter, with 1000 ohms/volt ormore sensitivity, to measure the potentialacross the resistor.4. Check each exposed metallic part, and measurethe voltage at each point.5. Reverse the AC plug in the AC outlet repeateach of the above measurements.6. The potential at any point should not exceed0.75 volts RMS. A leakage current tester(Simpson Model 229 equivalent) may be used tomake the hot checks, leakage current must notexceed 1/2 milliamp. In case a measurement isoutside of the limits specified, there is apossibility of a shock hazard, and theequipment should be repaired and recheckedbefore it is returned to the customer.ELECTROSTATICALLY SENSITIVE(ES) DEVICESSome semiconductor (solid state) devices can bedamaged easily by static electricity. Suchcomponents commonly are calledElectrostaticallySensitive (ES) Devices. Examples of typical ESdevices are integrated circuits and somefield-effect transistors and semiconductor "chip"components. The following techniques should beused to help reduce the incidence of componentdamage caused by static electricity.1. Immediately before handling any semiconductorcomponent or semiconductor-equipped assembly,drain off any electrostatic charge on your bodyby touching a known earth ground.Alternatively, obtain and wear a commerciallyavailable discharging wrist strap device, whichshould be removed for potential shock reasonsprior to applying power to the unit under test.2. After removing an electrical assembly equippedwith ES devices, place the assembly on aconductive surface such as aluminum foil, toprevent electrostatic charge buildup orexposure of the assembly.3. Use only a grounded-tip soldering iron tosolder or unsolder ES devices.4. Use only an anti-static solder removal deviceclassified as "anti-static" can generateelectrical charges sufficient to damage ESdevices.5. Do not use freon-propelled chemicals. These cangenerate electrical charges sufficient todamage ES devices.6. Do not remove a replacement ES device from itsprotective package untilimmediately before youare ready to install it. (Most replacementESdevices are packaged with leads eletcricallyshorted together by conductive foam, aluminumfoil or comparable conductive material).7. Immediately before removing the protectivematerial from the leads of replacement ESdevice, touch the protective material to thechassis or circuit assembly into which thedevice will be installed.CAUTION : Be sure no power is applied tothe chassis or circuit, and observe all otnerasfety precautions.8. Minimize bodily motions when handlingunpackaged replacement ES devices. (Otherwiseharmless motion such as the brushing togetherof your clothes fabric or the lifting of yourfoot from a carpeted floor can generate staticelectricity sufficient to damage an ES device).1-2