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4 Removal and replacement procedures
Preliminary replacement requirements
You will need the following tools to complete the removal and replacement procedures:
●Phillips P0 and P1 screwdrivers
●Torx T8 screwdriver
●5.0-mm (3/16-inch) nut driver
The following sections include some of the considerations that you must keep in mind during
disassembly and assembly procedures.
NOTE:As you remove each subassembly from the computer, place the subassembly (and all
accompanying screws) away from the work area to prevent damage.
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.
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Cables and connectors
CAUTION:When servicing the computer, be sure that cables are placed in their proper locations
during the reassembly process. Improper cable placement can damage the computer.
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. Be sure 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.
CAUTION:Drives are fragile components that must be handled with care. To prevent damage to the
computer, damage to a drive, or loss of information, observe these precautions:
Before removing or inserting a hard drive, shut down the computer. If you are unsure whether the
computer is off or in Hibernation, turn the computer on, and then shut it down through the operating
Before handling a drive, be sure that you are discharged of static electricity. While handling a drive,
avoid touching the connector.
Before removing a diskette drive or optical drive, be sure that a diskette or disc is not in the drive and
be sure that the optical drive tray is closed.
Handle drives on surfaces covered with at least one inch of shock-proof foam.
Avoid dropping drives from any height onto any surface.
After removing a hard drive, an optical 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 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.”
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Electrostatic discharge damage
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, ESD contains enough power to alter device parameters or melt silicon junctions.
A discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or
microcircuitry. Even if the spark is neither felt nor heard, damage may have occurred.
An electronic device exposed to ESD 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.
CAUTION:To prevent damage to the computer when you are removing or installing internal
components, observe these precautions:
Keep components in their electrostatic-safe containers until you area ready to install them.
Before touching an electronic component, discharge static electricity by using the guidelines described
in this section.
Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible.
If you remove a component, place it in an electrostatic-safe container.
The following table shows how humidity affects the electrostatic voltage levels generated by different
CAUTION:A product can be degraded by as little as 700 V.
Typical electrostatic voltage levels
Walking across carpet35,000 V15,000 V7,500 V
Walking across vinyl floor12,000 V5,000 V3,000 V
Motions of bench worker6,000 V800 V400 V
Removing DIPS from plastic tube2,000 V700 V400 V
Removing DIPS from vinyl tray11,500 V4,000 V2,000 V
Removing DIPS from Styrofoam14,500 V5,000 V3,500 V
Removing bubble pack from PCB26,500 V20,000 V7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V
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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 nonconductive
●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
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
●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
●Keep the work area free of nonconductive materials, such as ordinary plastic assembly aids and
●Handle ESD-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 removing connectors or test equipment.
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Grounding equipment must include either a wrist strap or a foot strap at a grounded workstation.
●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.
●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 strips must
be worn in contact with the skin.
The following grounding equipment is recommended to prevent electrostatic damage:
●Antistatic smocks, aprons, and sleeve protectors
●Conductive bins and other assembly or soldering aids
●Conductive tabletop workstations with ground cords of one megohm resistance
●Static-dissipative tables or floor mats with hard ties to the ground
●Field service kits
●Static awareness labels
●Nonconductive plastic bags, tubes, or boxes
●Metal tote boxes
●Electrostatic voltage levels and protective materials
The following table lists the shielding protection provided by antistatic bags and floor mats.
MaterialUseVoltage protection level
Antistatic plasticBags1,500 V
Carbon-loaded plasticFloor mats7,500 V
Metallized laminate Floor mats 5,000 V
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