HP 255 G4, Maintenance And Service Manual

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Avoid contact with pins, leads, or circuitry.
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Turn off power and input signals before inserting or removing connectors or test equipment.
Equipment guidelines
Grounding equipment must include either a wrist strap or a foot strap at a grounded workstation.
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When seated, wear a wrist strap connected to a grounded system. Wrist straps are flexible straps with a
minimum of one megohm ±10% resistance in the ground cords. To provide proper ground, wear a strap
snugly against the skin at all times. On grounded mats with banana-plug connectors, use alligator clips
to connect a wrist strap.
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When standing, use foot straps and a grounded floor mat. Foot straps (heel, toe, or 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 foot straps on both feet with a minimum of one megohm resistance
between the operator and ground. To be effective, the conductive must be worn in contact with the
skin.
The following grounding equipment is recommended to prevent electrostatic damage:
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Antistatic tape
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Antistatic smocks, aprons, and sleeve protectors
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Conductive bins and other assembly or soldering aids
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Nonconductive foam
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Conductive tabletop workstations with ground cords of one megohm resistance
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Static-dissipative tables or floor mats with hard ties to the ground
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Field service kits
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Static awareness labels
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Material-handling packages
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Nonconductive plastic bags, tubes, or boxes
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Metal tote boxes
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Electrostatic voltage levels and protective materials
The following table lists the shielding protection provided by antistatic bags and floor mats.
Material Use Voltage protection level
Antistatic plastics Bags 1,500 V
Carbon-loaded plastic Floor mats 7,500 V
Metallized laminate Floor mats 5,000 V
26 Chapter 4 Removal and replacement procedures preliminary requirements