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electrostatic voltage levels.
Table 4-1
Typical Electrostatic Voltages
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 tubes 2,000 V 700 V 400 V
Removing DIPS from vinyl trays 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 PCBs 26,000 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V
NOTE: 700 volts can degrade a product.
Preventing Electrostatic Damage to Equipment
Many electronic components are sensitive to ESD. Circuitry design and structure
determine the degree of sensitivity. The following proper packaging and grounding
precautions are necessary to prevent damage:
Protect all electrostatic parts and assemblies with conductive or approved
containers or packaging.
Keep electrostatic-sensitive parts in their containers until they arrive at
static-free stations.
Place items on a grounded surface before removing them from their
container.
Always be properly grounded when touching a sensitive component or
assembly.
Place reusable electrostatic-sensitive parts from assemblies in protective
packaging or conductive foam.
Use transporters and conveyors made of antistatic belts and metal roller bushings.
Mechanized equipment used for moving materials must be wired to ground and proper
materials selected to avoid static charging. When grounding is not possible, use an
ionizer to dissipate electric charges.
Removing Batteries
Compaq recommends that you remove all batteries from the computer before
beginning the disassembly procedures. Failure to do so could cause damage to
computer components.
4-2 Removal and Replacement Preliminaries
Preventing Damage to Drives
To prevent static damage to hard drives:
Handle drives gently, using static-guarding techniques.
Store drives in the original shipping containers.
Avoid dropping drives from any height onto any surface.
Handle drives on surfaces that have at least one inch of shockproof foam.
Always place drives with the PCB assembly-side down on the foam.
Grounding Methods
The method for grounding must include a wrist strap or a foot strap at
a grounded workstation. When seated, wear a wrist strap connected to a grounded
system. When standing, use footstraps and a grounded floor mat. Table 4-2 shows the
protection levels for each grounding method.
Table 4-2
Static-Shielding Protection Levels
Method Voltages
Antistatic plastic 1,500
Carbon-loaded plastic 7,500
Metallized laminate 15,000
Grounding Workstations
To prevent static damage at the workstation:
Cover the workstation with approved static-dissipative material. Provide a
wrist strap connected to the work surface and properly grounded tools and
equipment.
Use static-dissipative mats, heel straps, or air ionizers to give added protection.
Handle electrostatic sensitive components, parts, and assemblies by the case or PCB
laminate. Handle them only at static-free workstations.
Avoid contact with pins, leads, or circuitry.
Turn off power and input signals before inserting and removing connectors or test
equipment.
Use fixtures made of static-safe materials when fixtures must directly contact
dissipative surfaces.
Keep work area free of non-conductive materials such as ordinary plastic assembly
aids and Styrofoam.
Use field service tools, such as cutters, screwdrivers, and vacuums that are
conductive.
Use a portable field service kit with a static dissipative vinyl pouch that folds out of
a work mat. Also use a wrist strap and a ground cord for the work surface. Ground
the cord to the chassis of the equipment undergoing test or repair.
Removal and Replacement Preliminaries 4-3
Grounding Equipment
Use the following equipment to prevent static electricity damage to the equipment:
Wrist Straps are flexible straps with a minimum of 1 megohm +/- 10% resistance to
the ground cords. To provide proper ground, a strap must be worn snug against the
skin. On grounded mats without banana-plug connectors, connect a wrist strap with
alligator clips.
Heel straps/Toe straps/Bootstraps can be used at standing workstations and are
compatible with most types of boots and shoes. On conductive floors or dissipative
floor mats, use straps on both feet with a minimum of 1 megohm resistance between
operator and ground. To be effective, the conductive strips must be worn in contact
with the skin.
Recommended Materials and Equipment
Other materials and equipment that are recommended for use in preventing static
electricity include:
Anti-static tape
Anti-static smocks, aprons, and sleeve protectors
Conductive bins and other assembly or soldering aids
Conductive foam
Conductive table-top workstations with ground cord of 1 megohm
of resistance
Static dissipative table and floor mats with hard tie to ground
Field service kits
Static awareness labels
Wrist straps and footwear straps providing 1 megohm +/- 10% resistance
Material handling packages
Conductive plastic bags
Conductive plastic tubes
Conductive tote boxes
Metal tote boxes
Opaque shielding bags
Transparent metallized shielding bags
Transparent shielding tubes
4-4 Removal and Replacement Preliminaries
4.2 Service Considerations
Following are some considerations to keep in mind during the disassembly and
assembly of the computer.
Tool Requirements
Magnetic Torx T-8 screwdriver
Flat-bladed screwdriver (optional)
7-mm socket wrench
5-mm socket wrench/screw driver
Preloaded application diskettes
IMPORTANT: To reassemble the computer, set the Torx T-8 screwdriver to
3-inch lbs.
Cables and Connectors
Apply only the tension required to seat or unseat the cables during insertion or removal
from connectors. Handle cables by the connector or pull tabs whenever possible. In all
cases, avoid bending, twisting, or tearing the cables, and ensure that cables are placed
in such a way that they cannot be caught or snagged by parts being removed or
replaced.
CAUTION: Improper cable placement can cause severe damage to the unit. Ensure
that cables are placed in their proper location during the reassembly process when
servicing these computers.
4.3 Serial Number
The computer serial numbers should be provided to Compaq whenever requesting
information or ordering spare parts. The serial number is located on the rear of the
computer.
Removal and Replacement Preliminaries 4-5
4-6 Removal and Replacement Preliminaries
chapter
5
COMPUTER REMOVAL AND
REPLACEMENT PROCEDURES
This chapter provides the removal and replacement procedures for the computer.
5.1 Serial Number
The computer serial number should be provided to Compaq support when requesting
information or ordering spare parts. The serial number is displayed on the rear of the
CPU (Figure 5-1).
Figure 5-1. Serial Number
NOTE: This model does not have an AC connector port. It has a recessed, sealed
opening to allow docking with a convenience base.
Computer Removal and Replacement Procedures 5-1
5.2 Disassembly Sequence Chart
This chart shows the order in which disassembly procedures are performed:
5.3 Preparing the Computer for Disassembly
5.3.1 Disconnecting the AC Power
5.3.2 Undocking the Computer
5.3.3 Battery Pack
5.3.4 DualBay Devices
5.3.5 PCMCIA
5.4 Modem
5.5 CD-ROM or DVD-ROM Drive
5.6 Keyboard
5.7 Memory Expansion Board
5.8 Hard Drive
5.9 Lithium Real-Time Clock Battery
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