Appendix C: Static Precautions And Esd Strap; Static Sensitive Precautions; Esd Wrist Strap Safety Precautions - Motorola MTS LiTE Installation, Configuration And Basic Service Manual

6802800U74-AN

Appendix C: Static Precautions and ESD Strap

Appendix C
Static Precautions and ESD Strap
This Appendix covers the following topics:
• Static Sensitive Precautions on page 460
• ESD Wrist Strap Safety Precautions on page 460
C.1

Static Sensitive Precautions

The static grounding wrist strap (Motorola P/N 4280385A59) must always be used when handling any
board or module within the MTS. Many of the boards or modules used in the MTS equipment are
vulnerable to damage from static charges.
Extreme care must be taken while handling, shipping, and servicing these boards or modules. To avoid
static damage, observe the following precautions:
• Before handling, shipping, and servicing MTS equipment, connect a wrist strap to the grounding clip
on the equipment cabinet which is located at the bottom of the cabinet and marked with a yellow
label. This discharges any accumulated static charges.
WARNING: Use extreme caution when wearing a conductive wrist strap near sources of
high voltage. The low impedance provided by the wrist strap also increases the danger of
lethal shock should accidental contact with high voltage sources occur.
• Avoid touching any module, board circuitry, including any connector pins with your hands.
• Before removing a board or module, disconnect its individual power supply first.
• Avoid carpeted areas, dry environments, and certain types of clothing (silk, nylon, and so on) during
service or repair due to the possibility of static buildup.
• Apply power to the circuit under test before connecting low impedance test equipment (such as
pulse generators). When testing is complete, disconnect the test equipment before power is
removed from the circuit under test.
• Be sure to ground all electrically powered test equipment. Connect a ground lead (-) from the test
equipment to the board or module before connecting the test probe (+). When testing is complete,
remove the test probe first, then remove the ground lead.
• Lay all circuit boards and modules on a static dispersive surface (a proper antistatic map) when
removed from the system. This mat will be connected to ground through a high resistance element.
• Never use non-conductive material for packaging modules being transported. All modules should be
wrapped with anti-static packaging material. Replacement modules shipped from the factory are
packaged in a conductive material, for example, antistatic bag.
C.2

ESD Wrist Strap Safety Precautions

The ESD socket built into the cabinet housing provides a point to which a wire from a wrist strap can
be connected. This is for ESD (electrostatic discharge) protection.
ESD wrist strap use is critical in the following cases:
• Replacement of any module inside a box, which includes service of any modules in a base radio.
460