Panasonic TH-42PM50U Service Manual

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

Panasonic TH-42PM50U Service Manual Manual pdf 4 page image

measure the potential across the resistor.4. Check each exposed metallic part, and measure the voltage ateach point.5. Reverse the AC plug in the AC outlet and repeat each of the abovemeasurements.6. The potential at any point should not exceed 0.75 volts RMS. Aleakage current tester (Simpson Model 229 or equivalent) may beused to make the hot checks, leakage current must not exceed 1/2milliamp. In case a measurement is outside of the limits specified,there is a possibility of a shock hazard, and the equipment shouldbe repaired and rechecked before it is returned to the customer.3. Prevention of Electro Static Discharge (ESD) toElectrostatically Sensitive (ES) DevicesSome semiconductor (solid state) devices can be damaged easily by static electricity. Suchcomponents commonly are called Electrostatically Sensitive (ES) Devices. Examples of typicalES devices are integrated circuits and some field-effect transistors and semiconductor "chip"components. The following techniques should be used to help reduce the incidence ofcomponent damage caused by electro static discharge (ESD).1. Immediately before handling any semiconductor component orsemiconductor-equipped assembly, drain off any ESD on yourbody by touching a known earth ground. Alternatively, obtain andwear a commercially available discharging ESD wrist strap, whichshould be removed for potential shock reasons prior to applyingpower to the unit under test.2. After removing an electrical assembly equipped with ES devices,place the assembly on a conductive surface such as alminum foil,to prevent electrostatic charge buildup or exposure of theassembly.3. Use only a grounded-tip soldering iron to solder or unsolder ESdevices.4. Use only an anti-static solder removal device. Some solderremoval devices not classified as "anti-static (ESD protected)" cangenerate electrical charge sufficient to damage ES devices.5. Do not use freon-propelled chemicals. These can generateelectrical charges sufficient to damage ES devices.4