1. Explain the purpose of safe working conditions and procedures
1.1 Identify safety procedures and potential hazards for users and technicians
General Safety Guidelines
Follow the basic safety guidelines to prevent cuts, burns, electrical shock, and damage to eyesight. As is best practice, make sure that a fire extinguisher and first-aid kit are available in case of fire or injury.
CAUTION: Power supplies and monitors contain very high voltage. Do not wear the antistatic wrist strap when repairing power supplies or monitors.
CAUTION: Some printer parts may become very hot when in use and other parts may contain very high voltages. Make sure that the printer has had time to cool before making the repair. Check the printer manual for locations of various components that may contain high voltages. Some components may retain high voltages even after the printer is turned off.
Fire Safety Guidelines
Follow fire safety guidelines to protect lives, structures, and equipment. To avoid an electrical shock, and to prevent damage to the computer, turn off and unplug the computer before beginning a repair.
Fire can spread rapidly and be very costly. Proper use of a fire extinguisher can prevent a small fire from getting out of control. When working with computer components, always consider the possibility of an accidental fire and know how to react. If there is a fire, you should follow these safety procedures:
Never fight a fire that is out of control or not contained.
Always have a planned fire escape route before beginning any work.
Get out of the building quickly.
Contact emergency services for help.
Be sure to locate and read the instructions on the fire extinguishers in your workplace before you have to use them. Safety training may be available in your organization.
In the United States, there are four classifications for fire extinguishers. A different letter, color, and shape identifies each fire extinguisher classification. Each type of fire extinguisher has specific chemicals to fight different types of fires:
Class A – Paper, wood, plastics, cardboard
Class B – Gasoline, kerosene, organic solvents
Class C – Electrical equipment
Class D – Combustible metals
What types of fire extinguisher classifications are there in your country?
It is important to know how to use a fire extinguisher. Use the memory aid P-A-S-S to help you remember the basic rules of fws,ire extinguisher operation:
P - Pull the pin.
A - Aim at the base of the fire, not at the flames.
S - Squeeze the lever.
S - Sweep the nozzle from side to side
1.2 Identify safety procedures to protect equipment from damage and data from loss
Electrostatic discharge
(ESD), harsh climates, and poor-quality sources of electricity can cause damage
to computer equipment. Follow proper handling guidelines, be aware of
environmental issues, and use equipment that stabilizes power to prevent
equipment damage and data loss.
ESD
Static electricity is the buildup of an electric charge resting on a surface.
This buildup may zap a component and cause damage. This is known as
electrostatic discharge (ESD). ESD can be destructive to the electronics in a
computer system.
At least 3,000 volts of static
electricity must build up before a person can feel ESD. For example, static
electricity can build up on you as they walk across a carpeted floor. When you
touch another person, you both receive a shock. If the discharge causes pain or
makes a noise, the charge was probably above 10,000 volts. By comparison, less
than 30 volts of static electricity can damage a computer component.
ESD Protection Recommendations
ESD can cause permanent damage to electrical components. Follow these
recommendations to help prevent ESD damage:
- Keep all components in antistatic bags until you are
ready to install them.
- Use grounded mats on workbenches.
- Use grounded floor mats in work areas.
- Use antistatic wrist straps when working on computers.
Climate
Climate affects computer equipment in a variety of ways:
- If the environment temperature is too high, equipment
can overheat.
- If the humidity level is too low, the chance of ESD
increases.
- If the humidity level is too high, equipment can suffer
from moisture damage.
Power Fluctuation Types
Voltage is the force that moves electrons through a circuit. The movement of
electrons is called current. Computer circuits need voltage and current to
operate electronic components. When the voltage in a computer is not accurate
or steady, computer components may not operate correctly. Unsteady voltages are
called power fluctuations.
The following types of AC power
fluctuations can cause data loss or hardware failure:
- Blackout
– complete loss of AC power. A blown fuse, damaged transformer, or downed
power line can cause a blackout.
- Brownout
– reduced voltage level of AC power that lasts for a period of time.
Brownouts occur when the power line voltage drops below 80% of the normal
voltage level. Overloading electrical circuits can cause a brownout.
- Noise
– interference from generators and lightning. Noise results in unclean
power, which can cause errors in a computer system.
- Spike
– sudden increase in voltage that lasts for a very short period and
exceeds 100% of the normal voltage on a line. Spikes can be caused by
lightning strikes, but can also occur when the electrical system comes
back on after a blackout.
- Power surge
– dramatic increase in voltage above the normal flow of electrical
current. A power surge lasts for a few nanoseconds, or one-billionth of a
second.
Power Protection Devices
To help shield against power fluctuation issues, use protection devices to
protect the data and computer equipment:
- Surge Suppressor
– helps protect against damage from surges and spikes. A surge suppressor
diverts extra electrical voltage on the line to the ground.
- Uninterruptible Power Supply (UPS) – helps protect against potential electrical power
problems by supplying electrical power to a computer or other device. The
battery is constantly recharging while the UPS is in use. The UPS is able
to supply a consistent quality of power when brownouts and blackouts
occur. Many UPS devices are able to communicate directly with the operating
system on a computer. This communication allows the UPS to safely shut
down the computer and save data prior to the UPS losing all electrical
power.
- Standby Power Supply (SPS) – helps protect against potential electrical power
problems by providing a backup battery to supply power when the incoming
voltage drops below the normal level. The battery is on standby during the
normal operation. When the voltage decreases, the battery provides DC
power to a power inverter, which converts it to AC power for the computer.
This device is not as reliable as a UPS because of the time it takes to
switch over to the battery. If the switching device fails, the battery
will not be able to supply power to the computer. Figure 2 shows some
examples of surge suppressors, UPS, and SPS devices.
CAUTION:
Never plug a printer into a UPS device. UPS manufacturers suggest not plugging
a printer into a UPS for fear of overloading the UPS.
1.3 Identify safety procedures to protect the environment from contamination
Computers and peripherals contain materials that can be harmful to the environment.
Hazardous materials are sometimes called toxic waste. These materials can
contain high concentrations of heavy metals such as cadmium, lead, or mercury.
The regulations for the disposal of hazardous materials vary according to state
or country. Contact the local recycling or waste removal authorities in your
community for information about disposal procedures and services.
Material Safety and Data Sheet
A Material Safety and Data Sheet (MSDS) is a fact sheet that summarizes
information about material identification, including hazardous ingredients that
can affect personal health, fire hazards, and first aid requirements.The MSDS sheet contains chemical reactivity and incompatibility information
that includes spill, leak, and disposal procedures. It also includes protective
measures for the safe handling and storage of materials.
To determine if a material is
classified as hazardous, consult the manufacturer's MSDS. In the U.S., the
Occupational Safety and Health Administration (OSHA) requires that all
hazardous materials must be accompanied by an MSDS when transferred to a new
owner. The MSDS information included with products purchased for computer
repairs or maintenance can be relevant to computer technicians. OSHA also requires
that employees be informed about the materials that they are working with and
be provided with material safety information. In the United Kingdom, Chemicals
Hazard Information and Packaging for Supply Regulations 2002 (CHIP3) oversees
the handling of hazardous materials. CHIP3 requires chemical suppliers to
safely package and transport dangerous chemicals and to include a data sheet
with the product.
NOTE: The MSDS is valuable in
determining how to dispose of any potentially hazardous materials in the safest
manner. Always check local regulations concerning acceptable disposal methods
before disposing of any electronic equipment.
What organization governs the use of
hazardous chemicals in your country? Are MSDS sheets mandatory?
The MSDS contains valuable
information:
- The name of the material
- The physical properties of the material
- Any hazardous ingredients contained in the material
- Reactivity data, such as fire and explosion data
- Procedures for spills or leaks
- Special precautions
- Health hazards
- Special protection requirements
Computers and other computing
devices are eventually discarded because of one of the following reasons:
- Parts or components begin to fail more frequently as
the device ages.
- The computer becomes obsolete for the application for
which it was originally intended.
- Newer models have improved features.
Before discarding a computer or any
of its components, it is crucial to consider safe disposal of each separate
component.
Proper Disposal of Batteries
Batteries often contain rare earth metals that can be harmful to the
environment. Batteries from portable computer systems may contain lead,
cadmium, lithium, alkaline manganese, and mercury. These metals do not decay
and will remain in the environment for many years. Mercury is commonly used in
the manufacturing of batteries and is extremely toxic and harmful to humans.
Recycling batteries should be a
standard practice for a technician. All batteries, including lithium-ion,
nickel-cadmium, nickel-metal hydride, and lead-acid are subject to disposal
procedures that comply with local environmental regulations.
Proper Disposal of Monitors or CRTs
Handle monitors and CRTs with care. Extremely high voltage can be stored in
monitors and CRTs, even after being disconnected from a power source. CRTs
contain glass, metal, plastics, lead, barium, and rare earth metals. According
to the U.S. Environmental Protection Agency (EPA), CRTs may contain
approximately 4 lbs (1.8 kg) of lead. Monitors must be disposed of in
compliance with environmental regulations.
Proper Disposal of Toner Kits,
Cartridges, and Developers
Used printer toner kits and printer cartridges must be disposed of properly or
recycled. Some toner cartridge suppliers and manufacturers will take empty
cartridges for refilling. There are also companies that specialize in refilling
empty cartridges. Kits to refill inkjet printer cartridges are available but
are not recommended, because the ink may leak into the printer, causing
irreversible damage. This can be especially costly because using refilled
inkjet cartridges may also void the inkjet printer warranty.
Proper Disposal of Chemical Solvents
and Aerosol Cans
Contact the local sanitation company to learn how and where to dispose of the
chemicals and solvents used to clean computers. Never dump chemicals or
solvents down a sink or dispose of them in any drain that connects to public
sewers.
The
cans or bottles that contain solvents and other cleaning supplies must be
handled carefully. Make sure that they are identified and treated as special
hazardous waste. For example, some aerosol cans may explode when exposed to
heat if the contents are not completely used.
2. Identify tools and software used with personal computer components and their purposes
For every job there is the
right tool. Make sure that you are familiar with the correct use of each tool
and that the right tool is used for the current task. Skilled use of tools and
software makes the job less difficult and ensures that tasks are performed
properly and safely.
Software tools are available that
help diagnose problems. Use these tools to determine which computer device is
not functioning correctly.
A technician must document all
repairs and computer problems. The documentation can then be used as a
reference for future problems or for other technicians who may not have
encountered the problem before. The documents may be paper based, but
electronic forms are preferred because they can be easily searched for specific
problems.
2.1 Identify hardware tools and their purpose
A toolkit should contain all
of the tools necessary to complete hardware repairs. As you gain experience,
you will learn which tools to have available for different types of jobs.
Hardware tools are grouped into these four categories:
- ESD tools
- Hand tools
- Cleaning tools
- Diagnostic tools
ESD Tools
There are two ESD tools: the antistatic wrist strap and the antistatic mat. The
antistatic wrist strap protects computer equipment when grounded to a computer
chassis. The antistatic mat protects computer equipment by preventing static
electricity from accumulating on the hardware or on the technician.
Hand Tools
Most tools used in the computer assembly process are small hand tools. They are
available individually or as part of a computer repair toolkit. Toolkits range
widely in size, quality, and price.
Cleaning Tools
Having the appropriate cleaning tools is essential when maintaining or
repairing computers. Using these tools ensures that computer components are not
damaged during cleaning. Click each of the items in Figure 3 for more
information on cleaning tools.
Diagnostic
Tools
A digital multimeter and a loopback adapter are used to test hardware. Click
each of the items in Figure 4 for more information on diagnostic tools
2.2 Identify software tools and their purpose
A technician must be able to
use a range of software tools to help diagnose problems, maintain hardware, and
protect the data stored on a computer.
Disk Management Tools
You must be able to identify which software to use in different situations.
Disk management tools help detect and correct disk errors, prepare a disk for
data storage, and remove unwanted files.
- Format
– used to prepare a hard drive to store information
- Scandisk or Chkdsk
– used to check the integrity of files and folders on a hard drive by
scanning the file system. They may also check the disk surface for
physical errors
Defrag – used to optimize space on a hard drive to the following
disk management tools:
- Fdisk or Disk Management – used to create and
- allow faster access to programs and data
- Disk Cleanup
– used to clear space on a hard drive by searching for files that can be
safely deleted
- Disk Management
– a system utility used to manage hard drives and partitions, which
peforms tasks such as initializing disks, creating partitions, and
formatting partitions
- System File Checker (SFC) – a command-line utility that scans the operating
system critical files and replaces any files that are corrupted
Use the Windows XP boot disk for
troubleshooting and repairing corrupted files. The Windows XP boot disk is designed
to repair Windows system files, restore damaged or lost files, and reinstall
the operating system. Third-party software tools are available to assist in
troubleshooting problems.
Protection Software Tools
Each year, viruses, spyware, and other types of malicious attacks infect
millions of computers. These attacks can damage an operating system,
application, and data. Computers that have been infected may even have problems
with hardware performance or component failure.
To protect data and the integrity of
the operating system and hardware, use software designed to guard against
attacks and to remove malicious programs.
Various types of software are used
to protect hardware and data, there are:
- Windows XP Security Center – allows you to check the status of essential security
settings on the computer. The Security Center continuously checks to make
sure that the software firewall and antivirus programs are running. It also
ensures that automatic updates are set to download and install
automatically.
- Antivirus Program
– protects a computer against virus attacks.
- Spyware Remover
– protects against software that sends information about web surfing
habits to an attacker. Spyware can be installed without the knowledge or
consent of the user.
- Firewall
– a program that runs continuously to protect against unauthorized
communications to and from your computer.
2.3 Identify organizational tools and their purpose
It is important that a
technician document all services and repairs. These documents need to be stored
centrally and made available to all other technicians. The documentation can
then be used as reference material for similar problems that are encountered in
the future. Good customer service includes providing the customer with a
detailed description of the problem and the solution.
Personal Reference Tools
Personal Reference tools include troubleshooting guides, manufacturer manuals,
quick reference guides, and a repair journal. In addition to an invoice, a
technician keeps a journal of upgrades and repairs. The documentation in the
journal should include descriptions of the problem, possible solutions that
have been tried in order to correct the problem, and the steps taken to repair
the problem. Be sure to note any configuration changes made to the equipment
and any replacement parts used in the repair. This documentation will be
valuable when you encounter similar situations in the future.
- Notes
– Make notes as you go through the investigation and repair process. Refer
to these notes to avoid repeating previous steps and to determine what
steps to take next.
- Journal
– Document the upgrades and repairs that you perform. The documentation
should include descriptions of the problem, possible solutions that have
been tried in order to correct the problem, and the steps taken to repair
the problem. Be sure to note any configuration changes made to the
equipment and any replacement parts used in the repair. Your journal,
along with your notes, can be valuable when you encounter similar
situations in the future.
- History of repairs
– Make a detailed list of problems and repairs, including the date,
replacement parts, and customer information. The history allows a
technician to determine what work has been performed on a computer in the
past.
Internet Reference Tools
The Internet is an excellent source of information about specific hardware
problems and possible solutions:
- Internet search engines
- News groups
- Manufacturer FAQs
- Online computer manuals
- Online forums and chat
- Technical websites
Miscellaneous Tools
With experience, you will discover many additional items to add to the toolkit.
A working computer is also a valuable
resource to take with you on computer repairs in the field. A working computer
can be used to research information, download tools or drivers, or communicate
with other technicians.
Make
sure that the parts are in good working order before you use them. Using known
good working components to replace possible bad ones in computers will help you
quickly determine which component may not be working properly.
3. Implement proper tool use
Safety in the workplace is
everyone's responsibility. You are much less likely to injure yourself or
damage components when using the proper tool for the job.
Before cleaning or repairing equipment, check to
make sure that your tools are in good condition. Clean, repair, or replace any
items that are not functioning adequately
3.1 Demonstrate proper use of an antistatic wrist strap
As discussed previously, an
example of ESD is the small shock that someone receives when you walk across a
room with carpet and touch a doorknob. Although the small shock is harmless to
you, the same electrical charge passing from you to a computer can damage its
components. Wearing an antistatic wrist strap can prevent ESD damage to
computer components.
The purpose of an antistatic wrist
strap is to equalize the electrical charge between you and the equipment. The
antistatic wrist strap is a conductor that connects your body to the equipment
that you are working on. When static electricity builds up in your body, the
connection made by the wrist strap to the equipment, or ground, channels the electricity
through the wire that connects the strap.
The wrist
strap has two parts and is easy to wear:
- Wrap the strap around your wrist and secure it using
the snap or Velcro. The metal on the back of the wrist strap must remain
in contact with the skin at all times.
- Snap the connector on the end of the wire to the wrist
strap and connect the other end either to the equipment or to the same
grounding point that the antistatic mat is connected to. The metal
skeleton of the case is a good place to connect the wire. When connecting
the wire to equipment you are working on, choose an unpainted metal
surface. A painted surface does not conduct the electricity as well as
unpainted metal.
NOTE: Attach the wire on the same
side of the equipment as the arm wearing the antistatic wrist strap. This will
help to keep the wire out of the way while you are working.
Although wearing a wrist strap will
help to prevent ESD, you can further reduce the risks by not wearing clothing
made of silk, polyester, or wool. These fabrics are more likely to generate a
static charge.
NOTE: Technicians should roll up
their sleeves, remove scarfs or ties, and tuck in their shirts to prevent
interference from clothing. Ensure that earrings, necklaces, and other loose
jewelry are properly secured.
CAUTION:
Never wear an antistatic wrist strap if you are repairing a monitor or CRT
3.2 Demonstrate proper use of an antistatic mat
You may not always have the
option to work on a computer in a properly equipped workspace. If you can
control the environment, try to set up your workspace away from carpeted areas.
Carpets can cause the buildup of electrostatic charges. If you cannot avoid the
carpeting, ground yourself to the unpainted portion of the case of the computer
on which you are working before touching any components.
Antistatic Mat
An antistatic mat is slightly conductive. It works by drawing static
electricity away from a component and transferring it safely from equipment to
a grounding point:
- Lay the mat on the workspace next to or under the
computer case.
- Clip the mat to the case to provide a grounded surface
on which you can place parts as you remove them from the system.
Reducing the potential for ESD
reduces the likelihood of damage to delicate circuits or components.
NOTE: Always handle components by
the edges.
Workbench
When you are working at a workbench, ground the workbench and the antistatic
floor mat. By standing on the mat and wearing the wrist strap, your body has
the same charge as the equipment and reduces the probability of ESD
3.3 Demonstrate proper use of various hand tools
A technician needs to be able
to properly use each tool in the toolkit. This topic covers many of the various
hand tools used when repairing computers.
Screws
Match each screw with the proper screwdriver. Place the tip of the screwdriver
on the head of the screw. Turn the screwdriver clockwise to tighten the screw
and counterclockwise to loosen the screw
Screws can become stripped if you
over-tighten them with a screwdriver. A stripped screw may
get stuck in the screw hole, or it may not tighten firmly. Discard stripped
screws.
Flat Head ScrewdriverUse a flat head screwdriver when you are working with a
slotted screw. Do not use a flat head screwdriver to remove a Phillips head
screw. Never use a screwdriver as a pry bar. If you can not remove a component,
check to see if there is a clip or latch that is securing the component in
place.
CAUTION: If excessive force is
needed to remove or add a component, something is probably wrong. Take a second
look to make sure that you have not missed a screw or a locking clip that is
holding the component in place. Refer to the device manual or diagram for
additional information.
Phillips Head Screwdriver
Use a Phillips head screwdriver with crosshead screws. Do
not use this type of screwdriver to puncture anything. This will damage the
head of the screwdriver.
Hex Driver
Use a hex driver to loosen and tighten bolts that have a
hexagonal (six-sided) head. Hex bolts should not be over-tightened because the
threads of the bolts can be stripped. Do not use a hex driver that is too large
for the bolt that you are using.
CAUTION: Some tools are magnetized.
When working around electronic devices, be sure that the tools you are using
have not been magnetized. Magnetic fields can be harmful to data stored on
magnetic media. Test your tool by touching the tool with a screw. If the screw
is attracted to the tool, do not use the tool.
Part Retriever, Needle-Nose Pliers,
or Tweezers
As shown in Figure 6, the part retriever, needle-nose pliers, and tweezers can
be used to place and retrieve parts that may be hard to reach with your
fingers. Do not scratch or hit any components when using these tools.
CAUTION:
Pencils should not be used inside the computer to change the setting of
switches or to pry off jumpers. The pencil lead can act as a conductor and may
damage the computer components.
3.4 Demonstrate proper use of cleaning materials
Keeping computers clean
inside and out is a vital part of a maintenance program. Dirt can cause problems
with the physical operation of fans, buttons, and other mechanical components.
Figure 1 shows severe dust buildup on computer components. On electrical
components, an excessive buildup of dust will act like an insulator and trap
the heat. This insulation will impair the ability of heat sinks and cooling
fans to keep components cool, causing chips and circuits to overheat and fail.
CAUTION: Before cleaning any device,
turn it off and unplug the device from the power source.
Computer Cases and Monitors
Clean computer cases and the outside of monitors with a mild cleaning solution
on a damp, lint-free cloth. Mix one drop of dishwashing liquid with four ounces
of water to create the cleaning solution. If any water drips inside the case,
allow enough time for the liquid to dry before powering on the computer.
LCD Screens
Do not use ammoniated glass cleaners or any other solution on an LCD screen
unless the cleaner is specifically designed for the purpose. Harsh chemicals
will damage the coating on the screen. There is no glass protecting these
screens, so be gentle when cleaning them and do not press firmly on the screen.
CRT Screens
To clean the screens of CRT monitors, dampen a soft, clean, lint-free cloth
with distilled water and wipe the screen from top to bottom. Then use a soft,
dry cloth to wipe the screen and remove any streaking after you have cleaned
the monitor.
Clean dusty components with a can of
compressed air. Compressed air does not cause electrostatic buildup on
components. Make sure that you are in a well-ventilated area before blowing the
dust out of the computer. A best practice is to wear a dust mask to make sure
that you do not breathe in the dust particles.
Blow out the dust using short bursts
from the can. Never tip the can or use the compressed air can upside down. Do
not allow the fan blades to spin from the force of the compressed air. Hold the
fan in place. Fan motors can be ruined from spinning when the motor is not
turned on.
Component Contacts
Clean the contacts on components with isopropyl alcohol. Do not use rubbing
alcohol. Rubbing alcohol contains impurities that can damage contacts. Make
sure that the contacts do not collect any lint from the cloth or cotton swab.
Blow any lint off the contacts with compressed air before reinstallation.
Keyboard
Clean a desktop keyboard with compressed air or a small, hand-held vacuum
cleaner with a brush attachment.
CAUTION: Never use a standard vacuum
cleaner inside a computer case. The plastic parts of the vacuum cleaner can
build up static electricity and discharge to the components. Use only a vacuum
approved for electronic components.
Mouse
Use glass cleaner and a soft cloth to clean the outside of the mouse. Do not
spray glass cleaner directly on the mouse. If cleaning a ball mouse, you can
remove the ball and clean it with glass cleaner and a soft cloth. Wipe the
rollers clean inside the mouse with the same cloth. You may need to use a nail
file to clean the rollers on the mouse. Do not spray any liquids inside the
mouse.
1. Hardware
