HP 255 G4, Maintenance And Service Manual

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Typical electrostatic voltage levels
Relative humidity
Event 10% 40% 55%
Walking across carpet 35,000 V 15,000 V 7,500 V
Walking across vinyl floor 12,000 V 5,000 V 3,000 V
Motions of bench worker 6,000 V 800 V 400 V
Removing DIPS from plastic tube 2,000 V 700 V 400 V
Removing DIPS from vinyl tray 11,500 V 4,000 V 2,000 V
Removing DIPS from Styrofoam 14,500 V 5,000 V 3,500 V
Removing bubble pack from PCB 26,500 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V
Packaging and transporting guidelines
Follow these grounding guidelines when packaging and transporting equipment:
●
To avoid hand contact, transport products in static-safe tubes, bags, or boxes.
●
Protect ESD-sensitive parts and assemblies with conductive or approved containers or packaging.
●
Keep ESD-sensitive parts in their containers until the parts arrive at static-free workstations.
●
Place items on a grounded surface before removing items from their containers.
●
Always be properly grounded when touching a component or assembly.
●
Store reusable ESD-sensitive parts from assemblies in protective packaging or non-conductive foam.
●
Use transporters and conveyors made of antistatic belts and roller bushings. Be sure that mechanized
equipment used for moving materials is wired to ground and that proper materials are selected to avoid
static charging. When grounding is not possible, use an ionizer to dissipate electric charges.
Workstation guidelines
Follow these grounding workstation guidelines:
●
Cover the workstation with approved static-shielding material.
●
Use a wrist strap connected to a properly grounded work surface and use properly grounded tools and
equipment.
●
Use conductive field service tools, such as cutters, screwdrivers, and vacuums.
●
When fixtures must directly contact dissipative surfaces, use fixtures made only of static-
safe materials.
●
Keep the work area free of nonconductive materials, such as ordinary plastic assembly aids
and Styrofoam.
●
Handle ESD-sensitive components, parts, and assemblies by the case or PCM laminate. Handle these
items only at static-free workstations.
Grounding guidelines 25