Panasonic TH-50PF30U Service Manual

Also see for TH-50PF30U: Operating instructions Operating instructions Service manual

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Panasonic TH-50PF30U Service Manual Manual pdf 3 page image

TH-50PF30U1 Safety Precautions1.1. General Guidelines1. W hen conducting repairs and servicing, do not attempt to modify the equipment, its parts or its materials.2. W hen wiring units (with cables, flexible cables or lead wires) are supplied as repair parts and only one wire or som e of thewires have been broken or disconnected, do not attem pt to repair or re-wire the units. Replace the entire wiring unit instead.3. W hen conducting repairs and servicing, do not twist the Fasten connectors but plug them straight in or unplug them straightout.4. W hen servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated ordamaged by the short circuit.5. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properlyinstalled.6. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.1.1.1.Leakage Current Cold Check 1.1.2. Leakage Current Hot Check (SeeFigure 1 .)1. Plug the AC cord directly into the AC outlet. D o not usean isolation transform er for this check.2. Connect a 1.5kohm, 10 watts resistor, in parallel with a0.15|iF capacitors, between each exposed metallic parton the set and a good earth ground such as a w ater pipe,as shown in Figure 1 .3. Use an AC voltmeter, with 1000 ohm s/volt or more sensitivity, to measure the potential across the resistor.4. Check each exposed metallic part, and measure the voltage at each point.5. Reverse the AC plug in the AC outlet and repeat each ofthe above measurements.6. The potential at any point should not exceed 0.75 voltsRMS. A leakage current tester (Simpson Model 229 orequivalent) may be used to make the hot checks, leakagecurrent must not exceed 1/2 milliamp. In case a measurem ent is outside of the limits specified, there is a possibility of a shock hazard, and the equipm ent should berepaired and rechecked before it is returned to the customer.1. Unplug the AC cord and connect a jum per between thetwo prongs on the plug.2. Measure the resistance value, with an ohmmeter,between the jum pered AC plug and each exposed metallic cabinet part on the equipm ent such as screwheads,connectors, control shafts, etc. W hen the exposed metallic part has a return path to the chassis, the readingshould be between 1Mohm and 5.2Mohm.W hen the exposed metal does not have a return path tothe chassis, the reading must beO O .Figure 13