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TO 1-1-700 - Robins Air Force Base

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<strong>TO</strong> 1-1-<strong>700</strong><br />

vertently destroy the module. Maintenance personnel should<br />

refer to MIL-HDBK-773, MIL-HDBK-263, and MIL-STD-<br />

1686 for more detailed descriptions of ESD control measures.<br />

8.9.3.2.1 Packaging for electrostatic discharge protection<br />

requires the use of one or more of the following materials:<br />

• MIL-PRF-81705, Type II Barrier Material, Transparent,<br />

Waterproof, Electrostatic Protective, Static Dissipative.<br />

• Cushioning material, flexible, cellular<br />

• Cushioning material, plastic open cell.<br />

• PPP-C-1797, Cushioning Material, Resilient, Low<br />

Density, Unicellular, Polypropylene Foam.<br />

8.9.3.2.2 ESD items may be further protected in reusable A-<br />

A-59736, Type II, style D ESD Fast Pack Containers or<br />

shielded in a bag or pouch conforming to MIL-PRF-81705,<br />

Type I Barrier Material, Water Vapor-Proof, Grease-Proof,<br />

Electrostatic and Electromagnetic Protective (Opaque).<br />

8.9.3.2.3 Protection will be provided to prevent physical<br />

damage and to maintain leads and terminals in an as-whenmanufactured<br />

condition during handling and transportation.<br />

8.9.3.2.4 Packaging of ESD items shall be in accordance<br />

with MIL-E-17555 for electrostatic protection. Marking shall<br />

be in accordance with MIL-STD-129.<br />

8.9.3.3 Addressing Corrosion. ESD damage to communications<br />

electronics devices can be caused by voltage or current<br />

depending on the item's composition and construction. This<br />

damage can be caused by direct contact or by the electrostatic<br />

field associated with other charged items. It is important to<br />

note that some modern military circuits are sensitive to voltages<br />

as low as 25 volts. The threshold of sensitivity or voltage<br />

level required for a human being to feel a static discharge is<br />

approximately 3500 volts. Therefore, ESD devices can be<br />

damaged by maintenance personnel without their knowledge.<br />

ESD control measures must be employed to minimize the<br />

impact of ESD damage on communications electronics parts,<br />

assemblies, and equipment.<br />

8.9.3.3.1 Preventive Maintenance and Control. ESD<br />

devices must be protected from static fields and/or static discharge<br />

when being transported, handled, or stored. The following<br />

preventive measures will help provide this protection:<br />

a. Handle ESD devices only at protected work stations.<br />

These sites eliminate all sources of ESD with good<br />

grounding techniques by electrically bonding all the surfaces,<br />

tools, and furnishings together. A protective stool<br />

should also be used and any support equipment (soldering<br />

irons, text fixtures, test equipment, lights, etc.) must<br />

be grounded.<br />

b. ESD devices should be covered or packaged in ESDprotective<br />

packaging when not being handled.<br />

c. Conductive carriers protect static sensitive devices by<br />

shielding them from static. These carriers are used to<br />

transport, store, and ship static sensitive devices and<br />

should be placed on a conductive table top. This allows<br />

safe removal of their contents. Example of conductive<br />

carriers are conductive trays, boxes, and containers.<br />

d. Shunting mechanisms short circuit all the leads of a<br />

device. This enables the entire device to be at the same<br />

electrical potential and prevents ESD. Shunting mechanisms<br />

for discrete components include shorting clips,<br />

rings, and conductive foam. Conductive shunt bars are a<br />

type of shunting mechanism for printed circuit boards<br />

(PCBs).<br />

e. Nonconductive objects that can generate and hold different<br />

static potentials on different areas on their surface<br />

are poor conductors and cannot be grounded. Static neutralizing<br />

equipment should be used to eliminate static<br />

charges on nonconductive objects. Use of an ionized air<br />

blower will neutralize static charge by continuously<br />

blowing a cloud of ionized air over the surface.<br />

f. Personnel should not wear synthetic fiber clothes. Cotton<br />

clothes with short sleeves or a cotton smock over<br />

clothing are recommended.<br />

g. Work areas shall be clear of static hazards such as ordinary<br />

plastics, coffee cups, and candy wrappers.<br />

h. Personnel shall only use uninsulated hand tools when<br />

working with electrostatic sensitive devices. Don't use<br />

plastic-coated tweezers, plastic lead-forming tools, or<br />

plastic solder suckers. Also, personnel shall use only<br />

natural bristle brushes.<br />

8.9.3.3.2 ESD Protective System Repair and Treatment.<br />

Corrective maintenance of ESD protection systems<br />

depends on the type of protection system involved, size of the<br />

damaged area, and degree/type of corrosion. Control, treatment,<br />

and repair measures must be employed to minimize the<br />

impact of corrosion on ESD protection systems. Maintenance<br />

personnel should refer to Chapter 7 and paragraph 8.6 of this<br />

manual and the applicable equipment system specific technical<br />

manuals for specific repair procedures.<br />

8-40

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