Chapter 1

Basics of Computer Maintenance

1.1 General Concepts about PC and tech support

Information technology (IT) is the design, development, implementation, support, and
management of computer hardware and software applications. An IT professional must have a
strong understanding of computers, computer systems, and operating systems. A computer is an
electronic device that processes data into useful information. A typical computer system consists
of hardware and software components. Hardware refers to physical devices such as cases, storage
drives, keyboards, monitors, cables, and printers. Software includes the operating system and
various application programs that control and utilize the hardware to perform tasks. It is the
operating system and programs. The operating system instructs the computer how to operate.
Programs or applications perform different functions. These operations may include identifying,
accessing, and processing information. It is a key piece of software that performs several important
roles:

 To provide an interface with the user.

 To provide an interface for add-on devices.
 To provide a range of input output services to link the user and application programs to the
hardware.
 To provide system integrity, security and management.

Programs or applications perform different functions. Programs vary widely depending on the type
of information that will be accessed or generated. For example, instructions for balancing a
checkbook are very different from instructions for simulating a virtual reality world on the Internet.

Computers are categorized into several types depending on size, performance, purpose, data
handling.

 Based on Size

Computers vary in size, from powerful supercomputers for complex tasks to embedded systems
built for specific functions in everyday devices. Each type is designed to meet different
performance needs and applications.

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 Supercomputers are the most powerful computers in terms of processing power. They are used
for extremely complex computations and tasks that require massive data processing capabilities,
such as scientific simulations, weather forecasting, and modelling natural phenomena. It is
extremely powerful, used for complex scientific and research tasks.

Characteristics:

 High-performance processors and memory systems.

 Can perform billions or even trillions of calculations per second.
 Costly and require special environments (e.g., controlled cooling systems).
 Employed by manufacturing companies
 Rapid information processing

Examples:

 IBM Blue Gene

 Cray XT5

Mainframe computers, though less efficient than supercomputers, are still very expensive. It is
large and powerful computers designed to handle and process vast amounts of data quickly. They
are used by large organizations like banks, insurance companies, and government institutions for
tasks such as transaction processing, large-scale enterprise applications, and database
management.

Examples:

 IBM Z Series
 Unisys ClearPath

Minicomputers, also known as mid-range computers, are smaller than mainframes but still
capable of supporting multiple users and handling medium-scale tasks. They are typically used for
smaller businesses or industrial applications that require fewer resources than mainframes.
Characteristics:
 Less powerful than mainframes but still capable of running several programs
simultaneously.

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  Used in manufacturing control, research labs, and medium-sized organizations.
 Can support up to hundreds of users at once.
Examples:
 DEC VAX
 Digital Equipment Corporation (DEC)

Microcomputers are the most common type of computers used by individuals. They are designed
for general-purpose tasks such as browsing the internet, word processing, gaming, and other
personal or office activities. Microcomputers are based on a microprocessor, which integrates the
functions of a computer's central processing unit (CPU) on a single chip.
Characteristics:
 Typically smaller, affordable, and user-friendly.
 Found in homes, schools, and offices.
 Includes desktops, laptops, tablets, and smartphones.
Examples:
 Desktop PCs, Laptops, Tablets, Smartphones

Embedded computers are specialized computers that are designed to perform specific tasks and
are often built into other devices. These computers are not typically seen as separate units but are
an integral part of everyday objects, from household appliances to industrial machines.
Characteristics:
 Focused on specific functions, with minimal user interaction.
 Often run on low power and have limited resources.
 Commonly used in devices that require real-time processing.
Examples:
 Smart TVs, Washing Machines, Car Control Systems, Microwave Ovens

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  Based on Performance

Computers are classified by performance into workstations and servers. Workstations handle
demanding tasks, while servers manage resources and data for multiple users.

Workstations are high-performance computers designed for technical, scientific, or professional

applications that require greater processing power than regular personal computers (PCs).
Workstations are typically used for tasks such as 3D graphics rendering, video editing, computer-
aided design (CAD), and scientific simulations. They offer more powerful processors, higher RAM
capacities, and advanced graphics capabilities compared to regular personal computers.

Characteristics:

 High-performance processors (often multi-core or multi-threaded).

 Large amounts of memory (RAM), often expandable.
 Enhanced graphics processing units (GPUs) for rendering high-resolution images and
video.
 Reliable and capable of running demanding software applications simultaneously.
 Often used by engineers, designers, architects, and scientists for complex tasks.

Examples:

 Computer-Aided Design (CAD) Workstations: Used by engineers and architects to

design 2D and 3D models.
 Video Editing Workstations: High-performance systems used by filmmakers and content
creators for editing large video files.
 Scientific Research Workstations: Used in research labs for simulations, data analysis,
and modelling.

Servers are specialized computers designed to manage, store, and provide resources or services to
other computers (clients) over a network. They are built to handle large amounts of data, provide
access to websites, store files, and manage network communications. Servers are critical in
business and enterprise environments where multiple users need to access shared data and
resources simultaneously.

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 Characteristics:

 High processing power to handle multiple requests and manage extensive data.
 Increased storage capacity, often with redundancies (e.g., RAID configurations) for data
protection.
 Built for high availability and reliability, often operating 24/7 without interruption.
 Scalable to accommodate growing data and user needs.
 Provide services such as web hosting, file sharing, database management, and email
hosting.

Examples:

 Web Servers: These servers host websites and deliver web pages to users' browsers.
Examples include Apache HTTP Server and Nginx.
 Database Servers: Servers dedicated to storing and managing databases, like MySQL and
Microsoft SQL Server.
 File Servers: Provide centralized storage and management of files for multiple users in an
organization.
 Mail Servers: Handle the sending, receiving, and storage of email for users across a
network.
 Based on Purpose

Computers are classified by purpose into general-purpose and special-purpose types. General-
purpose computers can perform a wide range of tasks, while special-purpose computers are
designed for specific functions.

General-purpose computers are designed to handle a wide variety of tasks. They can be
programmed to perform a range of functions, from simple calculations to complex tasks. These
computers are flexible and can run many different types of software, making them suitable for
personal, educational, business, and entertainment use.

Characteristics:

 Can perform multiple tasks and be used for a variety of purposes.

 Capable of running many types of software applications.
 Users can install or update software as needed.
 Typically include personal computers, laptops, and workstations.

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 Examples:

 Personal Computers (PCs): These are the most common general-purpose computers used
for activities such as word processing, web browsing, and gaming.
 Laptops: Portable computers used for general-purpose tasks.
 Workstations: High-performance computers designed for technical and scientific work,
often used for tasks like video editing, 3D design, and software development.

Special-purpose computers are designed and optimized to perform a specific task or set of tasks.
Unlike general-purpose computers, they cannot be reprogrammed for other uses. These computers
are typically more efficient than general-purpose computers for the specific function they are
designed for. They are found in a wide range of devices and industries, from household appliances
to industrial machinery.

Characteristics:

 Designed to perform a specific, limited set of functions.

 Usually do not require user interaction beyond the task they are built for.
 Often optimized for speed and efficiency in their specific domain.
 Can be embedded within devices or machines for dedicated control.

Examples:

 Gaming Consoles: Devices like the PlayStation or Xbox, which are designed specifically
for playing video games.
 Calculators: Electronic devices designed to perform arithmetic calculations.
 Traffic Signal Controllers: Specialized systems are used to manage the flow of traffic at
intersections.
 ATM Machines: These are computers dedicated to banking transactions and cannot be
used for other tasks.
 Microwave Ovens: Embedded systems in appliances that perform specific tasks like
cooking food by controlling the temperature and time.
 Based on data handling

Computers are classified by data handling into analog, digital, and hybrid types. Analog handles
continuous data, digital processes binary data, and hybrid combines both methods.

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 Analog computers are designed to process continuous data. Instead of using digital numbers (0s
and 1s), these computers use physical quantities, such as voltage or current, to represent data.
Analog computers are especially good at simulating real-world phenomena that vary continuously,
like temperature, speed, or pressure.

Characteristics:

 Process continuous data (e.g., temperature, pressure).

 Used for tasks that require real-time simulations.
 Often used in scientific research, engineering, and control systems.

Examples:

 Speedometers: Measure the speed of a vehicle using continuous data.

 Thermometers: Measure temperature changes.
 Radar Systems: Measure distance by sending out continuous waves and processing

Digital computers process data in binary form (0s and 1s). They are the most common type of
computer and are capable of performing a wide range of tasks, from simple calculations to complex
simulations. Digital computers are versatile, reliable, and can handle large volumes of data quickly.

Characteristics:

 Process discrete data in binary format.

 Capable of performing arithmetic and logical operations.
 Used in personal computers, servers, and smartphones.

Examples:

 Personal Computers (PCs): Laptops, and desktops used for general tasks.
 Smartphones: Mobile devices for communication and entertainment.

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  Servers: High-performance systems that manage data and resources for multiple users.

Hybrid computers combine features of both analog and digital computers. They can process both
continuous (analog) and discrete (digital) data. Hybrid systems are designed to take advantage of
the strengths of both types of computers, making them highly useful in specific applications where
both types of data need to be processed simultaneously.

Characteristics:

 Combine the real-time processing capabilities of analog systems with the precision and
versatility of digital systems.
 Used in specialized applications that require both types of data.

Examples:

 Hospitals: Patient monitoring systems that measure heart rate (analog) and store data
digitally.
 Scientific Research: Systems that simulate complex phenomena and process both
continuous data (like temperature) and discrete data (like test results).
 Industrial Systems: Systems controlling factory machines where both analog sensors
(e.g., temperature) and digital control systems are used.

The computer technical support is a service that is responsible for giving the customer support
by different means to find a solution to the problem of the same, whether physical (hardware) or
logical (software) of any type of electronic device. The staff must be specialized in order to provide
a quality service to customers, on the one hand provide technical support to customers, but also
help to solve specific problems in different devices.

A computer technician not only works when something serious like a cyberattack occurs, but also
has a series of daily jobs that must be performed so that all computer devices in the company work
perfectly. Among them we can highlight checking vulnerable points in the security of systems,
installation of operating systems, verification of the operation of software and hardware, database
backups, system updates, configuration and installation of internal and external networks.

Technical support (Tech Support) provides assistance to users experiencing hardware, software,
or network issues. The goal is to ensure systems operate smoothly and efficiently. IT technical
support is the service provided by professionals to help users resolve hardware, software, or

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 network-related problems. Depending on how the service is delivered and the nature of the issue,
technical support can be categorized into several types:

1. Self-Support (User: - Based Support): In this method, users rely on available resources
such as user manuals, FAQs, community forums, and chatbots to diagnose and fix minor
issues independently. It reduces dependency on technicians and promotes user learning.
2. Remote Support: - This type of support allows technicians to access and troubleshoot
systems from a remote location through the internet using tools like TeamViewer,
AnyDesk, or Windows Remote Desktop. It saves time and cost since no physical visit is
required.
3. On-Site Support: - In cases where hardware replacement or network troubleshooting is
necessary, technicians visit the user’s physical location. On-site support is ideal for
resolving issues such as faulty cables, hardware installation, or server maintenance.
4. Help Desk Support: - The help desk is the first point of contact for users seeking technical
assistance. Support staff handle requests, record incidents, and perform basic
troubleshooting before escalating complex issues to higher-level technicians.
5. Tiered (Level-Based) Technical Support:
Many organizations use a tiered support structure to handle issues efficiently:
o Level 1 (L1): Basic troubleshooting and user guidance (password resets,
installation help).
o Level 2 (L2): Handles complex software, OS, and hardware issues.
o Level 3 (L3): Advanced specialists or developers who deal with system-level
problems or escalations.
6. Vendor or Third-Party Support: - Some specialized systems or software require external
vendor support. Vendors or service providers offer maintenance contracts or warranties
that cover updates, repairs, and technical assistance for specific products.

1.2 Lab Procedures and maintenance tools

Computer maintenance and technical support form the foundation for ensuring that computer
systems function efficiently, securely, and with minimal downtime. These activities include
preventive and corrective maintenance, troubleshooting, and following safety and laboratory
procedures. A computer laboratory is a specialized environment designed for practical training,
experimentation, and maintenance of computer systems. Proper lab procedures and the use of

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 appropriate maintenance tools are essential to ensure safety, efficiency, and reliability during all
technical operations.

Lab procedures are a set of standardized rules, safety measures, and professional practices
followed in a computer lab. They protect both the technicians and the equipment from harm, and
they promote a productive working environment.

Injury prevention is everyone’s responsibility. Stay alert to situations that could result in an injury.
Developing and using safe work practices is by far the best method for preventing injuries in the
workplace. In order to best prevent injury, follow these simple rules at all times:

 Follow all national, industry, and workplace safety rules.

 Be alert and be awake. A tired worker can be a danger to one’s self and others.
 Training is essential when working with electricity, power tools, or any other potentially
hazardous equipment.
 Use safety equipment, Protect people from injury, Protect equipment from damage
 Lift with the legs, not the back. Many back injuries are caused by people bending over to lift
a heavy object.
 The work place is never the place for drugs or alcohol.
 Always act professionally. Clowning around or playing practical jokes can result in injury.
 Stay current on issues related to safety and health in the workplace.
 Protect the environment from contamination

Before starting any task, technicians must:

 Wear appropriate clothing (avoid loose sleeves or jewelry that could catch on equipment).
 Arrange tools and materials in an orderly manner to prevent confusion or accidents.
 Disconnect power sources before opening or repairing any computer system.
 Label workstations and equipment properly for identification and accountability.

Safety is critical when working with electricity and electronic components. Every technician must:

 Follow electrostatic discharge (ESD) precautions by using antistatic wrist straps, mats,
and grounded outlets.
 Never work on a system while plugged in — always remove the power cord before
opening a computer case.

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  Avoid food and drinks in the lab to prevent spills and short circuits.
 Keep fire extinguishers and first aid kits accessible in case of emergencies.
 Be alert — fatigue or carelessness can lead to serious accidents.

Before and after any maintenance activity, proper documentation should be completed. This
includes:

 Recording system specifications (hardware configuration, software version, etc.).

 Logging all maintenance activities performed and tools used.
 Keeping maintenance and troubleshooting reports for future reference and
accountability.

After completing maintenance, the system must be tested and verified to ensure proper
functionality:

 Run hardware diagnostics to confirm all components are working.

 Verify software performance and reinstall missing drivers if necessary.
 Conduct a final inspection to check that cables, screws, and covers are properly secured.

Maintenance tools are devices, instruments, and software utilities used to inspect, repair, clean,
test, and optimize computer systems. They are classified into hardware tools, software tools,
and cleaning equipment.

 Identify hardware tools and their purpose

Specialized Tools

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.

Hardware tools: - are physical instruments used to assemble,

disassemble, and repair computer components.

 ESD Tools, include antistatic wrist strap and antistatic mat

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  An antistatic wrist strap is used to prevent ESD damage to computer equipment.
 An antistatic mat is used to stand on or to place hardware on
to prevent static electricity from building up.
 Hand Tools, include various screwdrivers, needle-nose pliers,
hex drivers, wire cutters, tweezers, part retriever, flashlight,
Assorted flat-blade screwdrivers, Assorted Phillips
screwdrivers, Assorted small nut drivers, Assorted small torx bit
drivers, Diagonal pliers

 Cleaning Tools, include soft cloth, compressed air can, cable

ties, and parts organizer,

 Diagnostic Tools, include digital multi-meter and loopback adapter

 Other related tools include

 Contact cleaner
 Foam swabs
 Cleaning supplies
 Magnifying glass
 Clip leads
 IC extractors

 Identify software tools and their purpose

Software Tools: - Software maintenance tools help maintain system performance, security, and
stability.
Disk Management
 Fdisk - used to create and delete partitions on a hard drive
 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 disk surface for physical errors

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  Defrag - used to optimize space on a hard drive to 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, such as
initializing disks, creating partitions, and formatting partitions. Disk Management has the
functions of FORMAT and FDISK, and a few more, but it is performed from the Windows
GUI interface.

 System File Checker (SFC) – a command-line utility that scans the operating system
critical files and replaces any files that are corrupted.

 Cleaning tools

Clean computer systems function more efficiently and last longer. Dust and debris can cause
overheating and hardware failure, so regular cleaning is essential. Common cleaning tools include:
 Soft Brushes – for removing dust from keyboards and circuit boards.
 Lint-Free Cloths – for wiping screens and external surfaces.
 Isopropyl Alcohol (70–90%) – for cleaning electronic contacts safely.
 Cotton Swabs – for cleaning small or delicate areas.
 Compressed Air Canisters – for dust removal from hard-to-reach areas.
 Vacuum Cleaners (ESD-safe) – for removing dust without generating static electricity.
Protection Software
 Windows XP Security Center or latest version
 Antivirus Program (AVG, Avira, McAfee, etc…)
 Spyware Remover
 Firewall

 Identify organizational tools and their purpose

Organizational Tools
It is important that a technician document all services and repairs. 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

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  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 (frequently asked questions)
 Online computer manuals
 Online forums and chat
 Technical websites
 Manufacturer download areas for new drivers
Miscellaneous tools – With experience, you will discover many additional items to add to the
toolkit. A working computer is 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. Using known good working components to replace possible
bad ones in computers will help you quickly determine which component may not be working
properly.

1.3 Static energy and its effects on computer

Static Electricity can cause numerous problems with a system. These problems usually appear
during the winter months, when humidity is low, or in extremely dry climates. Static electricity is
caused by dry climate and friction of substances in the climate. In these cases, you may need to
take special precautions to ensure that the systems can function properly.

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 The usual symptom is in the form of a parity-check (memory) error or a totally locked up
system. Any time the system unit is opened or you are handling circuits outside the system unit,
however, you must be careful with static. You can damage a component with static discharges if
these charges are not routed to a ground. It is recommended that you handle boards and adapters
by a grounding point first, to minimize the potential for any static damage.

But most static problems experienced by functional systems are caused by improper grounding.
One of the easiest ways to prevent static problems is with a solid stable ground, which is extremely
important for computer equipment.

A poorly designed grounding system is one of the largest causes of a poor computer design. A
good way to solve static problems is to prevent the static signal from getting into the computer in
the first place. The chassis ground in a properly designed system serves as a static guard for the
computer to redirect the static charge safely to the ground, which means that the system must be
plugged into a properly grounded three-wire outlet.

If the problem is extreme, you can resort to other measures. One is to use a properly grounded
static mat underneath the computer. Touch this mat first before touching the computer itself. This
procedure ensures that any static discharges are routed to the ground, away from the system unit
internals. If problems still persist, you may want to check out the electrical building ground.

Electricity in Computers: Static vs Dynamic

1. Dynamic Electricity: - Electricity that flows continuously through a conductor, like the current
in a wire. Computers use dynamic electricity (also called current or electric flow) to power all
components. Measured in volts (V) and amperes (A).

Examples: Powering the CPU, RAM, hard drives, motherboard, and peripherals.

2. Static Electricity: - Electricity stored in an object without flowing, usually caused by friction.

Effect on Computers:

 Static electricity can be dangerous to computer components.

 Even a tiny electrostatic discharge (ESD) can damage sensitive parts like CPU, RAM, or
motherboard.

Computers do not use static electricity as a power source; it’s something to prevent. Computers
use DC electricity internally. AC from the wall is converted to DC by the power supply.

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 Static electricity is the buildup of electric charge on an object, often caused by friction between
materials. When the charge is suddenly released, it results in electrostatic discharge (ESD).
Sensitive components such as memory modules, processors, and hard drives can be permanently
damaged by ESD.

ESD effects can be immediate, leading to burnt circuits, or latent, where components are weakened
and later fail. To prevent ESD, technicians must use grounding tools and follow proper safety
procedures.

Static electricity is generated through several common actions or environmental conditions, such
as:

 Friction: Rubbing certain materials together (e.g., clothing, carpets, or plastic surfaces).
 Dry Air: Low humidity increases static buildup because moisture normally helps dissipate
electric charges.
 Movement: Walking across a carpet or moving plastic chairs can cause electrons to
accumulate on your body.
 Handling Electronic Components: Touching circuit boards, RAM modules, or
processors without grounding can transfer static electricity from your body to the device.

Electrostatic Discharge (ESD) is the sudden transfer of static electricity between two objects with
different electrical potentials. When ESD occurs, a large amount of electrical energy can flow
through sensitive electronic circuits in a fraction of a second.

Computer components like memory modules, microprocessors, and hard drives are extremely
sensitive to ESD. A discharge as small as 30 volts far below what a human can feel can
permanently damage these components.

To minimize the risks of ESD, technicians should follow these best practices:

 Use Antistatic Wrist Straps and Mats: Connect yourself and the workstation to a
common ground to discharge static safely.
 Work in ESD-Safe Areas: Use grounded tables, ESD floor mats, and ionizers to neutralize
charges.
 Avoid Synthetic Clothing: Wear cotton clothing that doesn’t generate static.

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  Maintain Proper Humidity: Keep the lab’s relative humidity between 40–60% to reduce
charge buildup.
 Handle Components Correctly: Always hold circuit boards by the edges, avoiding metal
contacts or pins.
 Unplug Equipment Before Working: Disconnect from the power source before opening
the system unit

Generally,

Voltage Used by Computers

1. Internal Components (DC Voltage)

 Computers use DC (Direct Current) voltage supplied by the power supply unit (PSU).
 Common voltages inside a computer:

Voltage Used For

+12V CPU, GPU, cooling fans, hard drives, optical drives

+5V Motherboard circuits, USB ports, some older components

+3.3V RAM, chipset, and modern motherboard circuits

-12V / -5V Rarely used; older legacy components

2. From Wall Outlet (AC Voltage)

 Standard AC voltage from the wall:

o 110V–120V AC in North America
o 220V–240V AC in most other countries
 The PSU converts this AC voltage to the DC voltages needed by the computer.

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 1.4 Safety rules
 Electrical Precautions
Pull the plug. Do not work on a system, under any circumstances, while it is plugged in. Don't just
turn it off and think that's enough. It is prudent to disconnect all external cables from the PC before
opening it up. Because cables like network or phone cord may cause electric shock if not
disconnected from the computer.

Stay out of the power supply unless you know what you are doing. Similarly, do not open up your
monitor unless you are absolutely sure of what you are doing. You can electrocute yourself even
with the power disconnected when inside the monitor.

Watch out for components being left inside the box. Dropping a screw inside your case can be a
hazard if it isn't removed before the power is applied, because it can cause components to short-
circuit.

 Mechanical Precautions
Make sure you have a large, flat area to work on. That will minimize the chance of components
falling, getting bent, or getting lost. Don't tighten screws too far or you may strip them or make it
impossible to loosen them later.

Sometimes it makes sense to turn your machine on with the cover off the case, to see if something
works before replacing the cover. If you do this, be very careful to keep objects from accidentally
falling into the box.

 Data Precautions
Back up your data before you open the box, even if the work you are doing seems "simple". This
applies doubly to any upgrades or repairs that involve changes to the motherboard, processor or
hard disk since data is irreplaceable.

Make a copy of your system's BIOS settings before doing any major work or changing anything
in the BIOS.

 Electrostatic Discharge Precautions

Static electricity is a major enemy of computer components. Static electricity can zap and ruin
your CPU, memory or other components instantly. The safest way to avoid this problem is to work
at a static-safe station or use a commercial grounding strap. The chassis ground in a properly

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 designed system serves as a static guard for the computer to redirect the static charge safely to the
ground, which means that the system must be plugged into a properly grounded three-wire outlet.

 Safety with Children

If you have children, I'd be extra careful leaving an open machine lying around. Kids are inquisitive
and curiosity and live electrical equipment don't mix too well. In general, kids should always be
supervised when using a PC. This can help avoid both possible problems: the PC hurting the kids,
or the kids damaging the PC (or destroying data.)

Other safety rules

 Avoid putting computers on the same circuits as air conditioning
 Use spike suppressor to avoid damage from electrical spike
 Use voltage regulator to avoid problems with low voltage or brown-outs
 Use UPS (Uninterruptible power supply) to keep equipment running during power failure.

1.5 Preventive maintenance and troubleshooting

Maintenance is the process of keeping computer systems, hardware, and software in good
working condition by regularly checking, repairing, cleaning, or upgrading them. It ensures that
computers work efficiently, last longer, and do not break down unexpectedly.

Types of Maintenance

1. Preventive Maintenance: - Regular maintenance done to prevent problems before they occur.
It Minimize failures, improve performance, and extend system life.

 Examples:
o Cleaning dust from hardware.
o Running antivirus scans.
o Updating operating system and software.

2. Corrective Maintenance: - Performed after a fault has occurred to correct the problem. It restore
the system to proper working condition.

 Examples:
o Replacing a dead power supply.
o Reinstalling a corrupted operating system.

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 o Repairing a faulty hard drive.

3. Predictive Maintenance: - Uses monitoring tools and diagnostics to predict when a component
may fail, so action can be taken in advance. It prevent sudden breakdowns by detecting early
warning signs.

 Examples:
o Monitoring hard disk health with SMART tools.
o Checking CPU temperature with sensors.

4. Adaptive Maintenance: - Adjusting or updating a system to work with changes in the

environment or requirements. It keep the system compatible with new conditions.

 Examples:
o Updating software to work with a new operating system.
o Modifying network settings to work with new hardware.

5. Perfective Maintenance: - Enhancing or improving a system to add new features or increase

performance. It improve user experience and system capability.

 Examples:
o Upgrading RAM for faster performance.
o Adding new features to software.

Purpose of preventive maintenance

Preventive maintenance is used to reduce the likelihood of hardware or software problems by

systematically and periodically checking hardware and software to ensure proper operation.

To protect the computer, extend the life of the components, and protect the data, proper preventive
maintenance is required. Performance issues may arise without regular maintenance and cleaning.
Reliable and stable equipment is a result of good preventive maintenance procedures.

Benefits of preventive maintenance include reduced computer down time and repair costs,
Increased data protection, Extended life of the components, Increased equipment stability etc…

 Preventive maintenance is divided into Hardware maintenance and Software maintenance plus
system protection.

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 Hardware Preventive Maintenance

Make sure that the hardware is operating properly and protected

 Repair or replace any components that show signs of abuse or excess wear.
 Protect Monitors
 Protect Hard Disk Drives
 Protect Floppy Disk Drives
 Protect Input Devices
 Schedule Preventive Maintenance
 Remove the dust from fan intakes.
 Remove dust from power supply.
 Remove dust from components inside the computer.
 Clean mouse and keyboard.
 Check and secure any loose cables.
 Keep components clean in order to reduce the likelihood of overheating.
For example, some environments, such as construction sites, may require computer equipment to
be cleaned more often than other environments.

Software Preventive Maintenance

Verify that the installed software is current. Follow the policies of the organization when installing
security updates, operating system updates, and program updates. Many organizations do not allow
updates until extensive testing has been completed. This testing is done to confirm that the update
will not cause problems with the operating system and software.

 Review security updates.  Scan for viruses and spyware.

 Review software updates.  Remove unwanted programs.
 Review driver updates.  Scan hard drives for errors.
 Update virus definition files.  Defragment hard drives.

For example, high-traffic networks, such as a school network, may require additional
scanning and removal of malicious software or unwanted files. Before troubleshooting problems,
always follow the necessary precautions to protect data on a computer.

System Protection

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 Computer technicians should be aware of potential environmental hazard and know how to prevent
them from becoming a problem. A good place to start checking for environmental hazards is from
the incoming power source. The following sections deal with power-line issues and solutions.

Power-Line Protection
Typical power-supply variations fall into two categories:

 Transients. An overvoltage condition; Overvoltage conditions can be classified as spikes

(measured in nanoseconds) or as surges (measured in milliseconds).
 Sags. Sags can include voltage sags and brownouts. Voltage sag typically lasts only a few
milliseconds; a brownout can last for a protracted period of time.

In general, if several components go bad in a short period of time, or if components go bad more
often than usual at a given location, these are good indicators of power-related issues. Likewise,
machines that crash randomly and often could be experiencing power issues. If “dirty” power
problems are suspected, a voltage-monitoring device should be placed in the power circuit and left
for an extended period of time. These devices observe the incoming power over time and produce
a problem indicator if significant variations occur.

 Surge Suppressors

Inexpensive power-line filters, called surge suppressors, are good for cleaning up dirty commercial
power. These units passively filter the incoming power signal to smooth out variations. You must
consider two factors when choosing a surge suppresser:

 Clamping speed
 Clamping voltage
These units protect the system from damage, up to a specified point. However, large
variations, such as surges created when power is restored after an outage, can still cause
considerable data loss and damage. In the case of startup surges, making sure that the system is
turned off, or even disconnected from the power source, until after the power is restored is one
option. In the case of a complete shutdown, or a significant sag, the best protection from losing
programs and data is an uninterruptible power supply (UPS).

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  Uninterruptible Power Supplies
Uninterruptible power supplies are battery-based systems that monitor the incoming power and
kick in when unacceptable variations occur in the power source. The term UPS is frequently used
to describe two different types of power backup systems: - The first is a standby power system,
and the second is a truly uninterruptible power system.

The standby system monitors the power input line and waits for a significant variation to occur.
The batteries in this unit are held out of the power loop and draw only enough current from the
AC source to stay recharged. When an interruption occurs, the UPS senses it and switches the
output of the batteries into an inverter circuit that converts the DC output of the batteries into an
AC current, and voltage, that resembles the commercial power supply. This power signal is
typically applied to the computer within 10 milliseconds.

The uninterruptible systems do not keep the batteries offline. Instead, the batteries and converters
are always actively attached to the output of UPS. When an interruption in the supply occurs, no
switching of the output is required. The battery/ inverter section just continues under its own
power.

Standby systems do not generally provide a high level of protection from sags and spikes. They
do, however, include additional circuitry to minimize such variations. Conversely, an
uninterruptible system is an extremely good power-conditioning system. Because it always sits
between the commercial power and the computer, it can supply a constant power supply to the
system.

Troubleshooting process steps

Computer Troubleshooting is the systematic process of identifying, diagnosing, and resolving

problems or malfunctions in a computer system, its hardware, software, or network. It is the
method used to find out why a computer isn’t working correctly and to fix it.

Step 1 - Identify the problem

 During the troubleshooting process, gather as much information from the customer as
possible, but always respectfully.
 Use the following strategy during this step:

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 1. Start by using open-ended questions to obtain general information.
2. Continue using closed-ended (yes/no) questions to get relevant information.
3. Then document the responses in the work order and in the repair journal.
4. And lastly, verify the customer’s description by gathering data from the computer by
using applications such as:
 Event Viewer: When system, user, or software errors occur on a computer, the Event Viewer
is updated with information about the errors. The Event Viewer application records the
following information about the problem:
 What problem occurred
 Date and time of the problem
 Severity of the problem
 Source of the problem
 Event ID number
 Which user was logged in when the problem occurred
 Although the Event Viewer lists details about the error, you might need to further
research the solution.
 Device Manager: The Device Manager displays all of the devices that are configured on a
computer. Any device that the operating system determines to be acting incorrectly is flagged
with an error icon. This type of error has a yellow circle with an exclamation point (!). If a
device is disabled, it is flagged with a red circle and an "X". A yellow question mark (?)
indicates that the hardware is not functioning properly because the system does not know
which driver to install for the hardware.
 Beep Codes: Each BIOS manufacturer has a unique beep sequence for hardware failures.
When troubleshooting, power on the computer and listen. As the system proceeds through
the POST, most computers emit one beep to indicate that the system is booting properly. If
there is an error, you might hear multiple beeps. Document the beep code sequence, and
research the code to determine the specific hardware failure.
 BIOS Information: If the computer boots and stops after the POST, investigate the BIOS
settings to determine where to find the problem. A device might not be detected or configured
properly. Refer to the motherboard manual to make sure that the BIOS settings are accurate.

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  Diagnostic Tools: Conduct research to determine which software is available to help
diagnose and solve problems. There are many programs available that can help you
troubleshoot hardware. Often, manufacturers of system hardware provide diagnostic tools of
their own. For instance, a hard drive manufacturer, might provide a tool that you can use to
boot the computer and diagnose why the hard drive does not boot Windows.

Step 2 - Establish a theory of probable causes

 Crete a list of the most common reasons why the error would occur.
 List the easiest or most obvious causes at the top with the more complex causes at the bottom.

Step 3 – Determine an exact cause

 Determine the exact cause by testing the theories of probable causes one at a time, starting
with the quickest and easiest.
 After identifying an exact cause of the problem, determine the steps to resolve the problem.
 If the exact cause of the problem has not been determined after you have tested all your
theories, establish a new theory of probable causes and test it.

Step 4 – Implement the solution

 Sometimes quick procedures can determine the exact cause of the problem or even correct
the problem. If it does, you can go to step 5.
 If a quick procedure does not correct the problem, you might need to research the problem
further to establish the exact cause.
 Divide larger problems into smaller problems that can be analyzed and solved individually.

Step 5 – Verify solution and full system functionality

 Verify full system functionality and implement any preventive measures if needed.
 Ensures that you have not created another problem while repairing the computer.

Step 6 – Document findings

 Discuss the solution with the customer.

 Have the customer confirm that the problem has been solved.

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  Document the process:
 Problem description
 Steps to resolve the problem
 Components used in the repair

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