Panasonic TH-42PM50U Service Manual

Also see for TH-42PM50U: Operating instructions Service manual

Panasonic TH-42PM50U Service Manual Manual pdf 3 page image

2. Safety Precautions2.1. General Guidelines1. When servicing, observe the original lead dress. If a short circuitis found, replace all parts which have been overheated ordamaged by the short circuit.2. After servicing, see to it that all the protective devices such asinsulation barriers, insulation papers shields are properly installed.3. After servicing, make the following leakage current checks toprevent the customer from being exposed to shock hazards.2.1.1. Leakage Current Cold Check1. Unplug the AC cord and connect a jumper between the two prongson the plug.2. Measure the resistance value, with an ohmmeter, between thejumpered AC plug and each exposed metallic cabinet part on theequipment such as screwheads, connectors, control shafts, etc.When the exposed metallic part has a return path to the chassis,the reading should be between 1M and 5.2M . / When theexposed metal does not have a return path to the chassis, thereading must be .Figure 12.1.2. Leakage Current Hot Check (See Figure 1.)1. Plug the AC cord directly into the AC outlet. Do not use anisolation transformer for this check.2. Connect a 1.5k , 10 watts resistor, in parallel with a 0.15 Fcapacitors, between each exposed metallic part on the set and agood earth ground such as a water pipe, as shown in Figure 1.3. Use an AC voltmeter, with 1000 ohms/volt or more sensitivity, to3