compaq notebook evo n150 series User Manual

							4–2Maintenance and Service Guide
Removal and Replacement Preliminaries
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.
ÄCAUTION:When servicing the computer, ensure that cables are
placed in their proper locations during the reassembly process.
Improper cable placement can damage the computer.
4.3 Preventing Damage to
Removable Drives
Removable drives are fragile components that must be handled
with care. To prevent damage to the computer, damage to a
removable drive, or loss of information, observe the following
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, 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. 
						

							Removal and Replacement Preliminaries
Maintenance and Service Guide4–3

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 into 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 into a bubble pack
mailer or other suitable form of protective packaging and
label the package “Fragile: Handle With Care.” 
						

							4–4Maintenance and Service Guide
Removal and 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.
The device may function normally for awhile, 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. 
						

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Maintenance and Service Guide4–5

Place reusable electrostatic-sensitive parts from assemblies in
protective packaging or non conductive 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
were 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 removing
connectors or test equipment. 
						

							4–6Maintenance and Service Guide
Removal and Replacement Preliminaries
4.7 Grounding Equipment and Methods
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 megaohm ±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,
connect a wrist strap with alligator clips.

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-megaohm
resistance between the operator and ground. To be effective,
the conductive strips must be worn in contact with the skin.
Other grounding equipment recommended for use in preventing
electrostatic damage includes:

Antistatic tape

Antistatic smocks, aprons, and sleeve protectors

Conductive bins and other assembly or soldering aids

Non-conductive foam

Conductive tabletop workstations with ground cords of
one-megaohm resistance

Static-dissipative table or floor mats with hard tie to ground

Field service kits

Static awareness labels

Material-handling packages 
						

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Maintenance and Service Guide4–7

Non-conductive plastic bags, tubes, or boxes

Metal tote boxes

Electrostatic voltage levels and protective materials
Table 4-1 shows how humidity affects the electrostatic voltage
levels generated by different activities.
Table 4-2 lists the shielding protection provided by antistatic bags
and floor mats.
Ta b l e 4 - 1
Typical Electrostatic Voltage Levels
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 tube 2,000 V 700 V 400 V
Removing DIPS from vinyl tray 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 PCB 26,500 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V

A product can be degraded by as little as 700 volts.
Ta b l e 4 - 2
Static-Shielding Materials
Material Use Voltage Protection Level
Antistatic plastic Bags 1,500 V
Carbon-loaded plastic Floor mats 7,500 V
Metallized laminate Floor mats 5,000 V 
						

							Maintenance and Service Guide5–1
5
Removal and Replacement
Procedures
This chapter provides removal and replacement procedures.
All screws removed during disassembly are P0 Phillips screws.
There are 64 screws and screwlocks in 13 different sizes that must
be removed and replaced when servicing the computer. Make
special note of each screw size and location during removal and
replacement.
Refer to Appendix C, “Screw Listing,” for detailed information
on screw sizes, locations, and usage. 
						

							5–2Maintenance and Service Guide
Removal and Replacement Procedures
5.1 Serial Number
Report the computer serial number to Compaq when requesting
information or ordering spare parts. The serial number is located
on the bottom of the computer (Figure 5-1).
Figure 5-1. Serial Number Location 
						

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Maintenance and Service Guide5–3
5.2 Disassembly Sequence Chart
Use the following chart to determine the section number to be
referenced when removing computer components.
Ta b l e 5 - 1
Disassembly Sequence Chart
Section Description#ofScrews
Removed
5.3 Preparing the computer for disassembly 0
5.4 Computer feet 0
5.5 Hinge covers 0
5.6 Keyboard 2
5.7 Display 4
5.8 EMI shield 1
5.9 Top cover 18
5.10 TouchPad 5
5.11 Speakers 10
5.12 Microphone 0
5.13 Display lid switch board 1
5.14 Heat sink 5
5.15 Infrared board 1
5.16 System board 11
5.17 PC Card assembly 2
5.18 Mini PCI board 0
5.19 Disk cell real time clock (RTC) battery 0 
						

							5–4Maintenance and Service Guide
Removal and Replacement Procedures
5.3 Preparing the Computer for
Disassembly
Perform the following steps before disassembling the computer.
Consult the computerHardware Guidefor instructions on the
following steps:
1. Turn off the computer.
2. Disconnect the AC Adapter and all external devices.
3. Remove the battery pack.
4. Remove the hard drive.
5. Remove the Media Bay device.
5.4 Computer Feet
The computer feet are adhesive-backed rubber pads. The
computer feet are included in the Miscellaneous Plastics Kit
(spare part number 239039-001). Refer to Figure 5-2 for the
computer feet locations.
Figure 5-2. Replacing the Computer Feet