HP Compaq nw9440 Notebook PC
HP Compaq nx9420 Notebook PC
Document Part Number: 412725-003
May 2007
This guide is a troubleshooting reference used for maintaining
and servicing the computer. It provides comprehensive
information on identifying computer features, components, and
spare parts; troubleshooting computer problems; and performing
computer disassembly procedures.
Microsoft and Windows are U.S. registered trademarks of Microsoft
Corporation. Intel is a trademark or registered trademark of Intel
Corporation or its subsidiaries in the United States and other countries.
Bluetooth is a trademark owned by its proprietor and used by
Hewlett-Packard Company under license. SD Logo is a trademark of its
proprietor.
The information contained herein is subject to change without notice. The
only warranties for HP products and services are set forth in the express
warranty statements accompanying such products and services. Nothing
herein should be construed as constituting an additional warranty. HP shall
not be liable for technical or editorial errors or omissions contained herein.
Maintenance and Service Guide
HP Compaq nw9440 Notebook PC
HP Compaq nx9420 Notebook PC
Third Edition: May 2007
First Edition: March 2006
Document Part Number: 412725-003
The HP Compaq nw9440 Notebook PC and HP Compaq nx9420
Notebook PC offer advanced modularity, Intel® Core Duo
processors, and extensive multimedia support.
HP Compaq nw9440 Notebook PC and HP Compaq nx9420
Notebook PC
Maintenance and Service Guide1–1
Page 8
Product Description
1.1Features
■ The following processors, varying by computer model:
❏ Intel Core Duo T2600 (2.17-GHz)
❏ Intel Core Duo T2500 (2.00-GHz)
❏ Intel Core Duo T2400 (1.83-GHz)
❏ Intel Core Duo T2300 (1.66-GHz)
■ The following displays are available, varying by
computer model:
❏ 17.0-inch, WUXGA+WVA, TFT (1920 × 1200) with over
16.8 million colors with AntiGlare
❏ 17.0-inch, WSXGA+WVA, TFT (1680 × 1050) with over
16.8 million colors with AntiGlare
❏ 17.0-inch, WXGA+WVA, TFT (1440 × 900) with over
16.8 million colors with AntiGlare
❏ 17.0-inch, WSXGA+WVA, TFT (1680 × 1050) with over
16.8 million colors with BrightView
■ 100-, 80-, and 60-GB high-capacity hard drive, varying by
computer model
■ 256-MB DDR2 synchronous DRAM (SDRAM) at 533 MHz
and 667 MHz, expandable to 4.0 GB
■ Microsoft® Windows® XP Professional
■ Full-size Windows keyboard with numeric keypad
■ TouchPad and pointing stick pointing devices, including
a dedicated vertical scroll region (select models only)
■ Integrated 10 Base-T/100 Base-TX Ethernet local area
network (LAN) network interface card (NIC) with RJ-45 jack
■ Integrated high-speed 56K modem with RJ-11 jack
1–2Maintenance and Service Guide
Page 9
Product Description
■ Integrated wireless support for Mini Card IEEE 802.11a/b/g
or 802.11b/g Wireless LAN (WLAN) device
■ Support for one Type I or Type II PC Card slot, with support
for both 32-bit (CardBus) and 16-bit PC Cards, varying by
computer model
■ External 120- and 90-watt AC adapters with 3-wire power
If the computer you are servicing has an unknown password,
follow these steps to clear the password. These steps also
clear CMOS:
1. Prepare the computer for disassembly (refer to Section 5.3,
“Preparing the Computer for Disassembly,” for more
information).
2. Remove the real-time clock (RTC) battery (refer to
Section 5.9, “RTC Battery,” for more information on
removing and replacing the RTC battery).
3. Wait approximately 5 minutes.
4. Replace the RTC battery and reassemble the computer.
5. Connect AC power to the computer. Do not reinsert any
battery packs at this time.
6. Turn on the computer.
All passwords and all CMOS settings have been cleared.
1–4Maintenance and Service Guide
Page 11
1.3Power Management
The computer comes with power management features that
extend battery operating time and conserve power. The
computer supports the following power management features:
■ Standby
■ Hibernation
■ Setting customization by the user
■ Hotkeys for setting the level of performance
■ Battery calibration
■ Lid switch standby/resume
■ Power button
■ Advanced Configuration and Power Management (ACPM)
compliance
Product Description
Maintenance and Service Guide1–5
Page 12
Product Description
1.4External Components
The external components on the front of the computer are shown
below and described in Table 1-1.
Front Components
Tabl e 1-1
Front Components
ItemComponentFunction
1Wireless lightOn: An integrated wireless device, such as
a wireless local area network (LAN) device
and/or a Bluetooth® device, is turned on.
2Power light■ On: The computer is on.
■ Blinking: The computer is in standby.
■ Blinking rapidly: An AC adapter with a
higher power rating should be
connected.
■ Off: The computer is off or in hibernation.
1–6Maintenance and Service Guide
Page 13
Tabl e 1-1
Product Description
Front Components
(Continued)
ItemComponentFunction
3Battery light■ Amber: A battery pack is charging.
■ Green: A battery pack is close to full
charge capacity.
■ Blinking amber: A battery pack that is the
only available power source has reached
a low-battery condition. When the battery
reaches a critical low-battery condition,
the battery light begins blinking more
quickly.
■ Off: If the computer is connected to an
external power source, the light is turned
off when all batteries in the computer are
fully charged. If the computer is not
connected to an external power source,
the light is turned off until the battery
reaches a low-battery condition.
4Drive lightBlinking: The hard drive or optical drive is
being accessed.
5Display release latchOpens the computer.
6Stereo speakers (2)Produce stereo sound.
7Digital Media SlotSupports 7 optional digital memory card
The external components on the right side of the computer are
shown below and described in Table 1-2.
Right-Side Components
1–8Maintenance and Service Guide
Page 15
Tabl e 1-2
Right-Side Components
ItemComponentFunction
Product Description
1Audio-out
(headphone) jack
2Audio-in
(microphone) jack
3USB ports (2)Connect USB 1.1- and 2.0-compliant
4Optical driveSupports an optical disc. The type of optical
5RJ-45 (network) jackConnects an optional network cable.
Connect optional headphones or powered
stereo speakers. Also connects the audio
function of an audio/video device such as
a television or VCR.
Connects an optional monaural
microphone.
devices to the computer using a standard
USB cable, or connect an optional External
MultiBay II to the computer. The MultiBay II
must also be connected to an external
power source.
drive varies by model.
Maintenance and Service Guide1–9
Page 16
Product Description
The external components on the left side of the computer are
shown below and described in Table 1-3.
Left-Side Components
Tabl e 1-3
Left-Side Components
ItemComponentFunction
1Exhaust ventProvides airflow to cool internal
components.
To prevent overheating, do not
Ä
obstruct vents. Do not allow a hard
surface, such as a printer, or a soft
surface, such as pillows, thick rugs,
or clothing, to block airflow.
2Smart Adaptor power
connector
3External monitor portConnects an optional VGA external monitor
4S-Video-out jackConnects an optional S-Video device, such
5USB ports (2)Connect USB 1.1- and 2.0-compliant
1–10Maintenance and Service Guide
Connects an AC adapter or an optional
power adapter.
or projector.
as a television, VCR, camcorder, projector,
or video capture card.
devices to the computer using a standard
USB cable, or connect an optional External
MultiBay II to the computer. The MultiBay II
must also be connected to an external
power source.
Page 17
Tabl e 1-3
Product Description
Left-Side Components
(Continued)
ItemComponentFunction
61394 portConnects an optional 1394a device such
as a scanner, digital camera, or digital
camcorder.
7Smart card slotSupports optional smart cards.
8PC Card slotSupports optional Type I, Type II, or
Type III 32-bit (CardBus) or 16-bit
PC Cards.
Maintenance and Service Guide1–11
Page 18
Product Description
The external components on the rear panel of the computer are
shown below and described in Table 1-4.
Rear Panel Components
1–12Maintenance and Service Guide
Page 19
Product Description
Table 1-4
Rear Panel Components
ItemComponentFunction
1Security cable slotAttaches an optional security cable to the
computer.
Security solutions are designed to
Ä
act as deterrents. These deterrents
may not prevent a product from
being mishandled or stolen.
2Battery bayHolds a battery pack.
3Exhaust ventProvides airflow to cool internal
4RJ-11 (modem) jackConnects the modem cable.
components.
To prevent overheating, do not
Ä
obstruct vents. Do not allow a hard
surface, such as a printer, or a soft
surface, such as pillows, thick rugs,
or clothing, to block airflow.
Maintenance and Service Guide1–13
Page 20
Product Description
The standard keyboard components of the computer are shown
below and described in Table 1-5.
Standard Keyboard Components
1–14Maintenance and Service Guide
Page 21
Product Description
Table 1-5
Standard Keyboard Components
ItemComponentFunction
1f1 to f12 keys (12)Perform system and application tasks.
When combined with the fn key, several
keys and buttons perform additional tasks
as hotkeys.
2caps lock keyEnables caps lock and turns on the
caps lock light.
3fn
4Windows logo keyIn Windows, displays the Windows
5Windows
6Arrow keysMoves the cursor around the screen.
keyExecutes frequently used system
functions when pressed in combination
applications key
with a function key or the
Start menu.
In Windows, displays a shortcut menu
for items beneath the pointer.
esc key.
7Keypad keys (16)In Windows, can be used like the keys
8num lock keyEnables numeric lock, turns on the
Maintenance and Service Guide1–15
on an external numeric keypad.
embedded numeric keypad, and turns
on the num lock light.
Page 22
Product Description
The computer top components are shown below and described in
Table 1-6.
Top Components
Table 1-6
Top Components
ItemComponentFunction
1Power light■ On: The computer is on.
■ Blinking: The computer is in standby.
■ Blinking rapidly: An AC adapter with a
higher power rating should be
connected.
■ Off: The computer is off or in
hibernation.
Power buttonWhen the computer is:
■ Off, press to turn on the computer.
■ On, briefly press to initiate hibernation.
■ In standby, briefly press to resume from
standby.
■ In hibernation, briefly press to restore
from hibernation.
If the system has stopped responding and
Windows shutdown procedures cannot be
used, press and hold for 5 seconds to turn
off the computer.
1–16Maintenance and Service Guide
Page 23
Table 1-6
Product Description
Top Components
(Continued)
ItemComponentFunction
2Wireless buttonTurns the wireless functionality on or off,
but does not create a wireless connection.
To establish a wireless connection,
✎
a wireless network must already be
set up.
Wireless lightOn: An integrated wireless device, such as
a wireless local area network (LAN) device
and/or a Bluetooth® device, is turned on.
3Info Center buttonEnables you to view a list of commonly
Presentation mode
button
QuickLaunch
Calculator button
4Caps lock lightOn: caps lock is on.
used software solutions.
Turns on Presentation mode.
Opens the Microsoft Windows calculator.
This button can also be reassigned to an
Internet or network destination or to any
software application or data file.
When you press the QuickLaunch
✎
calculator button, num lock is
enabled.
5Num lock lightOn: num lock or the numeric keypad is on.
6Volume mute buttonMutes or restores speaker volume.
7Volume down buttonDecreases speaker volume.
8Volume up buttonIncreases speaker volume.
Maintenance and Service Guide1–17
Page 24
Product Description
The computer pointing device components shown below and
described in Table 1-7.
Pointing Device Components
1–18Maintenance and Service Guide
Page 25
Table 1-7
Pointing Device Components
ItemComponentFunction
Product Description
1Pointing stick
(select models only)
2Pointing stick buttons
(select models only)
3TouchPadMoves the pointer and selects or activates
4Fingerprint reader
(select models only)
5TouchPad buttons (2 or
3 buttons, varying by
computer model)
6TouchPad scroll zoneScrolls up or down.
Moves the pointer and selects or activates
items on the screen.
Function like the left, middle, and right
buttons on an external mouse.
items on the screen. Can be set to perform
other mouse functions, such as scrolling,
selecting, and double-clicking.
Allows a fingerprint logon to Windows
instead of using a password.
Function like the left, middle, and right
buttons on an external mouse.
Maintenance and Service Guide1–19
Page 26
Product Description
The external components on the bottom of the computer are
shown below and described in Table 1-8.
Bottom Components
Table 1 - 8
Bottom Components
ItemComponentFunction
1Primary battery bayHolds the primary battery pack.
2Primary battery locking
latch
3Docking connectorConnects the computer to an optional
4Accessory battery
connector
1–20Maintenance and Service Guide
Secures the primary battery pack into
the battery bay.
docking device.
Connects an optional HP Ultra-Capacity
Battery or HP Extended Life Battery.
Page 27
Table 1 - 8
Product Description
Bottom Components
(Continued)
ItemComponentFunction
5Memory module
compartment
Mini Card compartment
6Hard drive bayHolds the primary hard drive.
7Primary battery release
latch
8Exhaust ventsProvides airflow to cool internal
Contains one memory slot that supports
replaceable memory modules.
Holds an optional wireless LAN device.
To prevent an unresponsive
Ä
system and the display of a
warning message, install only a
Mini Card device authorized for
use in your computer by the
governmental agency that
regulates wireless devices in
your country. If you install a
device and then receive a
warning message, remove
the device to restore computer
functionality. Then contact
Customer Care.
Releases the primary battery pack from
the battery bay.
components.
To prevent overheating, do not
Ä
obstruct fans. Do not allow a hard
surface, such as a printer, or a
soft surface, such as pillows,
thick rugs, or clothing, to block
airflow.
Maintenance and Service Guide1–21
Page 28
Product Description
1.5Design Overview
This section presents a design overview of key parts and features
of the computer. Refer to Chapter 3, “Illustrated Parts Catalog,”
to identify replacement parts, and Chapter 5, “Removal and
Replacement Procedures,” for disassembly steps.
The system board provides the following device connections:
■ Audio
■ Display
■ Hard drive
■ Intel Core Duo processors
■ Keyboard and TouchPad
■ Memory modules
■ Mini Card module
■ PC Card
CAUTION: To properly ventilate the computer, allow at least a 7.6-cm
Ä
(3-inch) clearance on the left and right sides of the computer.
The computer uses an electric fan for ventilation. The fan is
controlled by a temperature sensor and is designed to be turned
on automatically when high temperature conditions exist. These
conditions are affected by high external temperatures, system
power consumption, power management/battery conservation
configurations, battery fast charging, and software applications.
Exhaust air is displaced through the ventilation grill located on
the left side of the computer.
1–22Maintenance and Service Guide
Page 29
Troubleshooting
WARNING: Only authorized technicians trained by HP should repair
Å
this equipment. All troubleshooting and repair procedures are detailed
to allow only subassembly-/module-level repair. Because of the
complexity of the individual boards and subassemblies, do not attempt
to make repairs at the component level or modifications to any printed
wiring board. Improper repairs can create a safety hazard. Any
indication of component replacement or printed wiring board
modification may void any warranty or exchange allowances.
2.1 Computer Setup
Computer Setup is a preinstalled, ROM-based utility that can be
used even when the operating system is not working or will not
load.
Some of the Computer Setup menu items listed in this guide
✎
may not be supported by your computer.
2
Pointing devices are not supported in Computer Setup. You
✎
must use the keyboard to navigate and make selections.
An external keyboard connected by USB can be used with
✎
Computer Setup only if USB legacy support is enabled.
The information and settings in Computer Setup are accessed
from the File, Security, Diagnostics, and System Configuration
menus.
Maintenance and Service Guide2–1
Page 30
Troubleshooting
1. Open Computer Setup by turning on or restarting the
computer, and then pressing
Based Setup” message is displayed in the lower-left corner of
the screen.
In Computer Setup, the following shortcuts are available:
❏ To change the language, press f2.
❏ To view navigation information, press f1.
❏ To close open dialog boxes and return to the main
2. Select the Files, Security, Diagnostics, or System
Configuration menu.
3. To exit Computer Setup, choose one of the following
methods:
❏ To exit Computer Setup without saving your preferences,
❏ To save your preferences and exit Computer Setup, use
Your preferences go into effect with the computer restarts.
f10 while the “F10 = ROM
Computer Setup screen
esc.
use the arrow keys to select File > Ignore Changes and
Exit. Then follow the instructions on the screen.
the arrow keys to select File > Save Changes and Exit.
Then follow the instructions on the screen.
2–2Maintenance and Service Guide
Page 31
Computer Setup Defaults
To return all settings in Computer Setup to the values that were
set at the factory:
1. Open Computer Setup by turning on or restarting the
computer, and then pressing
Based Setup” message is displayed in the lower-left corner of
the screen.
In Computer Setup, the following shortcuts are available:
❏ To change the language, press f2.
❏ To view navigation information, press f1.
❏ To close open dialog boxes and return to the main
Computer Setup screen
2. Use the arrow keys to select File > Restore defaults, and
then press
enter.
esc.
Troubleshooting
f10 while the “F10 = ROM
3. When the confirmation dialog box opens, press
4. Select the Restore defaults check box, and then press
5. To confirm the restoration, press
6. To save your preferences and exit Computer Setup, use the
arrow keys to select File > Save Changes and Exit. Then
follow the instructions on the screen.
Your preferences go into effect when the computer restarts.
Your password and security settings are not changed when you
✎
restore the factory default settings.
Maintenance and Service Guide2–3
f10.
f10.
enter.
Page 32
Troubleshooting
Computer Setup Menus
The menu tables in this section provide an overview of Computer
Setup options.
Some of the Computer Setup menu items listed in this chapter
✎
may not be supported by your computer.
Table 2 - 1
File Menu
SelectTo Do This
System Information■ View identification information for the computer
and the battery packs in the system.
■ View specification information for the
processor, cache and memory size, system
ROM, video revision, and keyboard controller
version.
Restore defaultsReplace the configuration settings in Computer
Setup with factory default settings. (Password and
security settings are not changed when you
restore the factory default settings.)
Ignore changes and exit Cancel changes entered during the current
session. Then exit and restart the computer.
Save changes and exitSave changes entered during the current session.
Then exit and restart the computer. Your changes
go into effect when the computer restarts.
2–4Maintenance and Service Guide
Page 33
Troubleshooting
Table 2 - 2
Security Menu
SelectTo Do This
Setup passwordEnter, change, or delete a setup password.
Power-on passwordEnter, change, or delete a power-on password.
■ Enable/disable password requirement on
computer restart.
DriveLock passwords■ Enable/disable DriveLock on any computer
hard drive and optional MultiBay hard drives.
■ Change a DriveLock user or master password.
DriveLock settings are accessible only
✎
when you enter Computer Setup by turning
on (not restarting) the computer.
Smart Card securityEnable/disable support for smart card and Java™
Card power-on authentication.
Power-on authentication for smart cards is
✎
supported only on computers with optional
smart card readers.
TPM Embedded SecurityEnable/disable support for TPM (Trusted Platform
Module) Embedded Security, which protects the
computer from unauthorized access to owner
functions in Embedded Security for ProtectTools.
For more information, refer to the ProtectTools
Security Manager Reference Guide located in the
Help and Support Center, or refer to Credential
Manager for ProtectTools online Help.
Maintenance and Service Guide2–5
Page 34
Troubleshooting
Table 2 - 2
Security Menu
SelectTo Do This
System IDsEnter user-defined computer asset and
ownership tag.
Disk SanitizerRun Disk Sanitizer to destroy all existing data on
the primary hard drive. The following options are
available:
✎
✎
✎
Ä
(Continued)
Fast: Runs the Disk Sanitizer erase cycle
once.
Optimum: Runs the Disk Sanitizer erase
cycle 3 times.
Custom: Allows you to select the desired
number of Disk Sanitizer erase cycles from
a list.
If you run Disk Sanitizer, the data on the
primary hard drive is destroyed
permanently.
Table 2 - 3
Diagnostics Menu
SelectTo Do This
Memory CheckRun a comprehensive check on system memory.
Hard Drive Self-Test
options
2–6Maintenance and Service Guide
Run a comprehensive self-test on any hard drive
in the system or on any optional MultiBay hard
drive.
Page 35
Troubleshooting
Table 2 - 4
System Configuration Menu
SelectTo Do This
Language (or press f2).Change the Computer Setup language.
Boot options■ Set f9, f10, and f12 delay when starting up.
■ Enable/disable CD-ROM boot.
■ Enable/disable Floppy boot.
■ Enable/disable internal network adapter boot
and set the boot mode (PXE or RPL).
■ Enable/disable MultiBoot, which sets a boot
order that can include most boot devices in
the system.
■ Set the boot order.
Maintenance and Service Guide2–7
Page 36
Troubleshooting
Table 2 - 4
System Configuration Menu
SelectTo Do This
Device configurations■ Swap the functions of the fn key and left ctrl
key.
■ Enable/disable multiple standard pointing
devices at startup. (To set the computer to
support only a single, usually nonstandard,
pointing device at startup, select Disable.)
■ Enable/disable USB legacy support. When
enabled, USB legacy support allows a USB
keyboard, mouse, and hub to work in Computer
Setup even when a Microsoft Windows
operating system is not loaded.
■ The computer to start from bootable USB
devices, including a hard drive, diskette drive
diskette, or optical drive connected by a USB
port to the computer or to an optional docking
device (select models only).
■ Automatic/disable Intel SpeedStep Technology.
■ Select a parallel port mode: EPP (Enhanced
Parallel Port), standard, bidirectional, or ECP
(Enhanced Capabilities Port).
■ Enable/disable BIOS DMA data transfers
(select models only).
■ Enable/disable the system fan when connected
to an AC outlet.
■ Enable/disable Intel or AMD PSAE Execution
Disable. When enabled, the processor can
disable some virus code execution, which helps
to improve computer security.
■ Enable/disable LAN Power Save. When
enabled, saves power by turning off the LAN
when not in use.
The following sections include some of the considerations
that you should keep in mind during disassembly and assembly
procedures.
As you remove each subassembly from the computer, place
✎
the subassembly (and all accompanying screws) away from
the work area to prevent damage.
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
CAUTION: When servicing the computer, ensure that cables are
Ä
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. 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.
4–2Maintenance and Service Guide
Page 95
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 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, and then shut it down
through the operating system.
■ Before removing a diskette drive or optical drive, ensure that
a diskette or disc is not in the drive and 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 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: Handle With Care.”
Maintenance and Service Guide4–3
Page 96
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 might not
be affected at all and can work perfectly throughout a normal
cycle. Or the device might function normally for a while, then
degrade in the internal layers, reducing its life expectancy.
4–4Maintenance and Service Guide
Page 97
Removal and Replacement Preliminaries
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.
■ Store reusable electrostatic-sensitive parts from assemblies
in protective packaging or nonconductive foam.
■ Use transporters and conveyors 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.
Maintenance and Service Guide4–5
Page 98
Removal and Replacement Preliminaries
4.6 Workstation Precautions
Use the following grounding precautions at workstations:
■ Cover the workstation with approved static-shielding material
(refer to
■ 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 fixtures must directly contact dissipative surfaces, use
fixtures made only 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.
Table 4-2, “Static-Shielding Materials”).
4–6Maintenance and Service Guide
Page 99
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 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.
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.
■ Nonconductive foam.
■ 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.
■ Material-handling packages.
■ Nonconductive plastic bags, tubes, or boxes.
■ Metal tote boxes.
■ Electrostatic voltage levels and protective materials.
Maintenance and Service Guide4–7
Page 100
Removal and Replacement Preliminaries
Table 4-1 shows how humidity affects the electrostatic voltage
levels generated by different activities.
Tabl e 4-1
Typical Electrostatic Voltage Levels
Relative Humidity
Event10%40%55%
Walking across carpet35,000 V15,000 V7,500 V
Walking across vinyl floor12,000 V 5,000 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 box21,000 V11,000 V5,000 V
A product can be degraded by as little as 700 V.
✎
Table 4-2 lists the shielding protection provided by antistatic
bags and floor mats.
Table 4 - 2
Static-Shielding Materials
MaterialUseVoltage Protection Level
Antistatic plasticBags1,500 V
Carbon-loaded plasticFloor mats7,500 V
Metallized laminateFloor mats5,000 V
4–8Maintenance and Service Guide
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