Panasonic TX-20LA5F Service Manual

Also see for TX-20LA5F: Operating instructions

Contents

Panasonic TX-20LA5F Service Manual Manual pdf 3 page image

PREVENTION OF ELECTROSTATIC DISCHARGE (ESD) TOELECTROSTATICALLY SENSITIVE (ES) DEVICESSome semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly arecalled Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effecttransistors and semiconductor "chip" components. The following techniques should be used to help reduce the incidence ofcomponent damage caused by electrostatic discharge (ESD).1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any ESD onyour body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESDwrist strap, which should be removed for potential shock reasons prior to applying power to the unit under test.2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such asaluminum foil, to prevent electrostatic charge build up or exposure of the assembly.3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.4. Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static (ESDprotected)" can generate electrical charge sufficient to damage ES devices.5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it.(Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foilor comparable conductive material).7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protectivematerial to the chassis or circuit assembly into which the device will be installed.CAUTIONBe sure no power is applied to the chassis or circuit, and observe all other safety precautions.8. Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise harmless motion such as thebrushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity(ESD) sufficient to damage an ES device).TOAPPLIANCESEXPOSEDMETAL PARTSResistance values in ohms (Ω)VR0 =500ΩRS=500Ω CS=500μF10kΩ0.022μFU1COLDWATER PIPE(EARTH GROUND)V: Voltmetr or oscilloscope(r.m.s. or peak reading)Measuring network for TOUCH CURRENTSFig. 2Input resistance: ≥ 1MΩInput capacitance: ≤ 200pFFrequency range: 15Hz to 1Mhz and d.c.respectivelyNOTE – Appropriate measures should be taken to obtain the correct value in case of non-sinusoidal waveformsThere are special components used in this equipment which are important for safety.These parts are marked by in schematic diagrams, exploded views and replacement parts list. It is essential thatthese critical parts should be replaced with manufacturer’s specified parts to prevent shock, fire, or other hazards. Donot modify the original design without permission of manufacturer.IMPORTANT SAFETY NOTICE3U2 (V)