Nortel DualMode 800, Руководство по обслуживанию

Страница: 86 / 216

3-4 Test equipment and precautions
411-2051-500 Draft 00.01 November 1999
RF radiation hazard
Radio Frequency (RF) radiation is hazardous to anyone working in the cell site.
All RF cables should be connected properly and all unused RF ports should be
terminated with an appropriate terminator.
Electrostatic Discharge (ESD) control
This section provides general guidelines and precautions for handling,
transporting and storing components and printed circuit wiring boards that are
susceptible to permanent damage when subjected to electrostatic discharge
(ESD).
ESD sensitive equipment
Various electrical and electronic components are vulnerable to electrostatic
discharge (ESD). These include:
• discrete components
• hybrid devices
• Integrated Circuits (ICs)
• boards assembled with these devices
Identification
Manufacturers vary in their methods of identifying static-sensitive equipment.
They may apply stickers or mark components with various colors, but many do
not indicate that their products are sensitive. Examples of identification are:
• circuit boards with ESD-sensitive devices have a red edge
• hybrids containing Metal-Oxide Semiconductors (MOS) devices are red,
with the letters MOS on the back. Non-sensitive hybrids are white.
• pull-handles on circuit packs containing sensitive devices may have the
letters MOS and the assembly part number printed in red
• assembly drawings may have manufacturing notes describing the circuits
as ESD-sensitive
CAUTION
RF radiation hazard
Do NOT disconnect any RF cables when transmitters are on.
CAUTION
Equipment damage
When in doubt, any circuit board containing microelectronic
components must be assumed to be vulnerable.