●Always be properly grounded when touching a sensitive component or assembly.

●Avoid contact with pins, leads, or circuitry.

●Place reusable electrostatic-sensitive parts from assemblies in protective packaging or conductive foam.

Personal Grounding Methods and Equipment

Use the following equipment to prevent static electricity damage to equipment:

●Wrist straps are flexible straps with a maximum of one-megohm ± 10% resistance in the ground cords. To provide proper ground, a strap must be worn snug against bare skin. The ground cord must be connected and fit snugly into the banana plug connector on the grounding mat or workstation.

●Heel straps/Toe straps/Boot straps can be used at standing workstations and are compatible with most types of shoes or boots. On conductive floors or dissipative floor mats, use them on both feet with a maximum of one-megohm ± 10% resistance between the operator and ground.

 

Static Shielding Protection Levels

 

 

Method

Voltage

 

 

Antistatic plastic

1,500

Carbon-loaded plastic

7,500

Metallized laminate

15,000

 

 

Grounding the Work Area

To prevent static damage at the work area, use the following precautions:

●Cover the work surface with approved static-dissipative material. Provide a wrist strap connected to the work surface and properly grounded tools and equipment.

●Use static-dissipative mats, foot straps, or air ionizers to give added protection.

●Handle electrostatic sensitive components, parts, and assemblies by the case or PCB laminate. Handle them only at static-free work areas.

●Turn off power and input signals before inserting and removing connectors or test equipment.

●Use fixtures made of static-safe materials when fixtures must directly contact dissipative surfaces.

●Keep work area free of nonconductive materials such as ordinary plastic assembly aids and Styrofoam.

●Use field service tools, such as cutters, screwdrivers, and vacuums, that are conductive.

Recommended Materials and Equipment

Materials and equipment that are recommended for use in preventing static electricity include:

●Antistatic tape

●Antistatic smocks, aprons, or sleeve protectors

16 Chapter 4 Identifying the Chassis, Routine Care, and Disassembly Preparation