Xerox PHASER 6250, Руководство по обслуживанию

Страница: 9 / 474

Service Manual vii
Electrostatic Discharge (ESD) Precautions
Some semiconductor components , and the respective sub-assemblies that contain
them, are vulnerable to damage by Electrostatic discharge (ESD). These components
include Integrated Circuits (ICs), Large-Scale Integrated circuits (LSIs), field-effect
transistors and other semiconductor chip components. The following techniques will
reduce the occurrence of component damage caused by static electricity.
Be sure the power is off to the chassis or circuit board, and observe all other safety
precautions.
■ Immediately before handling any semiconductor components assemblies, drain
the electrostatic charge from your body. This can be accomplished by touching an
earth ground source or by wearing a wrist strap device connected to an earth
ground source. Wearing a wrist strap will also prevent accumulation of additional
bodily static charges. Be sure to remove the wrist strap before applying power to
the unit under test to avoid potential shock.
■ After removing a static sensitive assembly from its anti-static bag, place it on a
grounded conductive surface. If the anti-static bag is conductive, you may ground
the bag and use it as a conductive surface.
■ Do not use freon-propelled chemicals. These can generate electrical charges
sufficient to damage some devices.
■ Do not remove a replacement component or electrical sub-assembly from its
protective package until you are ready to install it.
■ Immediately before removing the protective material from the leads of a
replacement device, touch the protective material to the chassis or circuit
assembly into which the device will be installed.
■ Minimize body motions when handling unpackaged replacement devices.
Motion such as your clothes brushing together, or lifting a foot from a carpeted
floor can generate enough static electricity to damage an electro-statically
sensitive device
■
Handle IC’s and EPROM’s carefully to avoid bending pins.
■ Pay attention to the direction of parts when mounting or inserting them on
Printed Circuit Boards (PCB’s).