Assessments - 2, GPA: 4 ( )

Fabricante : Apple Arquivo Tamanho: 4.63 mb Arquivo Nome : Língua de Ensino:

Plastic Parts Using excessive force during disassembly and reassembly can damage plastic parts. Use care when handling the plastic parts. Apply pressure only at the points designated in the maintenance instructions. Cables and Connectors Cables must be handled with extreme care to avoid damage. Apply only the tension required to unseat or seat the cables during removal and insertion. Handle cables by the connector whenever possible. In all cases, avoid bending, twisting, or tearing cables. Ensure that cables are routed in such a way that they cannot be caught or snagged by parts being removed or replaced. Handle flex cables with extreme care; these cables tear easily. A A CAUTION: When servicing the notebook, ensure that cables are placed in their proper locations during the reassembly process. Improper cable placement can damage the notebook. 4–2 Maintenance and Service Guide Removal and Replacement Preliminaries 4.3 Preventing Damage to Removable Drives Removable drives are fragile components that must be handled with care. To prevent damage to the notebook, damage to a removable drive, or loss of information, observe the following precautions: ¦ Before removing or inserting a hard drive, shut down the notebook. If you are unsure whether the notebook is off or in Hibernation, turn the notebook on, then shut it down. ¦ Before removing a diskette drive or optical drive, ensure that a diskette or disc is not in the drive. Ensure that the optical drive tray is closed. ¦ Before handling a drive, ensure that you are discharged of static electricity. While handling a drive, avoid touching the connector. ¦ Handle drives on surfaces that have at least one inch of shock-proof foam. ¦ Avoid dropping drives from any height onto any surface. ¦ After removing a hard drive, CD-ROM drive, or a diskette drive, place it in a static-proof bag. ¦ Avoid exposing a hard drive to products that have magnetic fields, such as monitors or speakers. ¦ Avoid exposing a drive to temperature extremes or to liquids. ¦ If a drive must be mailed, place the drive in a bubble-pack mailer or other suitable form of protective packaging and label the package “Fragile: Handle With Care.” Maintenance and Service Guide 4–3 Removaland Replacement Preliminaries 4.4 Preventing Electrostatic Damage Many electronic components are sensitive to electrostatic discharge (ESD). Circuitry design and structure determine the degree of sensitivity. Networks built into many integrated circuits provide some protection, but in many cases the discharge contains enough power to alter device parameters or melt silicon junctions. A sudden discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to electrostatic discharge may not be affected at all and can work perfectly throughout a normal cycle. Or the device may function normally for a while, then degrade in the internal layers, reducing its life expectancy. 4.5 Packaging and Transporting Precautions Use the following grounding precautions when packaging and transporting equipment: ¦ To avoid hand contact, transport products in static-safe containers, such as tubes, bags, or boxes. ¦ Protect all electrostatic-sensitive parts and assemblies with conductive or approved containers or packaging. ¦ Keep electrostatic-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 sensitive component or assembly. 4–4 Maintenance and Service Guide Removal and Replacement Preliminaries ¦ Store reusable electrostatic-sensitive parts from assemblies in protective packaging or nonconductive foam. ¦ Use transporters and conveyers made of antistatic belts and roller bushings. Ensure 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. 4.6 Workstation Precautions Use the following grounding precautions at workstations: ¦ Cover the workstation with approved static-dissipative material (refer to Table 4-2). ¦ 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 using fixtures that must directly contact dissipative surfaces, only use fixtures made of static-safe materials. ¦ Keep the work area free of nonconductive materials, such as ordinary plastic assembly aids and Styrofoam. ¦ Handle electrostatic-sensitive components, parts, and assemblies by the case or PCM laminate. Handle these items only at static-free workstations. ¦ Avoid contact with pins, leads, or circuitry. ¦ Turn off power and input signals before inserting or rem...

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