Safety Precautions; Prevention Of Electro Static Discharge(Esd)To Electrostatically Sensitive(Es)Devices - Cambridge Audio DVD53 Service Manual

1. SAFETY PREAUTIONS
1.1 GENERAL GUIDELINES
1. When servicing, observe the original lead dress. if a short circuit is found, replace all parts which have
been overheated or damaged by the short circuit.
2. After servicing, see to it that all the protective devices such as insulation barrier, insulation papers
shields are properly installed.
3. After servicing, make the following leakage current checks to prevent the customer from being exposed
to shock hazards.
2.PREVENTION OF ELECTRO STATIC DISCHARGE(ESD)TO
ELECTROSTATICALLY SENSITIVE(ES)DEVICES
Some semiconductor(solid state)devices can be damaged easily by static electricity. Such components
commonly are called Electrostatically Sensitive(ES)Devices. Examples of typical ES devices are integrated
circuits and some field-effect transistors and semiconductor chip components. The following techniques
should be used to help reduce the incidence of component damage caused by electro static discharge(ESD).
1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain
off any ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially
availabel discharging ESD wrist 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 as alminum foil, to prevent electrostatic charge buildup 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
(ESD protected)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, alminum foil or comparable conductive material).
7. Immediately before removing the protective material from the leads of a replacement ES device, touch
the protective material to the chassis or circuit assembly into which the device will be installed.
Caution
Be 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 the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can
generate static electricity(ESD).
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