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I. Computer Service EssentialsSAFETY PRECAUTIONS Power Supply Unit (PSU)Dont dismantle

Minor electrocution may occasionally occur. Dont touch the terminals while power is being supplied

Minor burns may occasionally occur. Do not touch the Product while power is being supplied

Fire may occasionally occur. Tighten the terminal screws with the specified torque.

Minor electric shock, fire, or Product failure may occasionally occur. Do not allow any pieces of metal or conductors or any clippings or cuttings resulting from installation work to enter the Product.

Fire Safety A Wood and Paper

B Flammable Liquids

C Electrical Wires / Equipment

Central Processing Unit (CPU)Never spray cleaning liquids directly unto any part of your computerDo not spray canned compressed air with the can upside downDo not touch any internal CPU component without wearing an anti-static wrist band or using an anti-static matDo not use a standard vacuum to clean inside your computerUnplug the computer monitor and allow it to cool before cleaningDo not leave a computer plugged in while cleaning

MonitorAlways keep your monitor clean or your monitor screen should be regularly wiped overDont fix your monitor if you have no experience to clean itDont let your thrash and food near the monitorDo not touch an LCD screen with your fingersDo not attempt to clean the inside of a computer monitorDo not use an unapproved liquid to clean your LCD screenKeyboard/MouseEnsure that the retractable legs on your keyboard are pulled back, allowing the keyboard to lay flat.Ensure that the contacts inside your mouse are clean to allow for smooth useKeyboard and mouse should be regularly disinfected as they are a breeding ground for all sorts of bacteriaEnsure that the mouse cord out of the way safely to avoid trip over and accidentAvoid eating and drinking near your keyboard and mouseAvoid playing the mouse and keyboard to avoid severe damage to it

PrinterDo not touch the ribbon of the printerDont shake or turn the cartridge upside downDont put the objects into the feeding systemLaser printers generate a laser that is hazardous to your eyesIf its an ink-jet printer, dont try to blow in the ink cartridges to clear a clogged opening Some parts of a laser printer (like the EP Cartridge) will be damaged if touch

TOOLS OF THE TRADE Behind every great technician is an even greater set of tools.There are two major types of tools: - Hardware Tools - Software ToolsHardware ToolsHardware tools are hard, meaning you can touch them, as opposed to software tools, which cannot be touched. Screwdrivers The tool that can most often found in a technician toolkit.Three major types: Flat-Blade Screwdriver Is often called flathead screwdriver, though most people simply refer it as standard screwdriver. Phillips Screwdriver The most common used type of screwdriver for computers today. It is used because they have more surfaces to turn against, reducing risk of damaging of the head of the screw. Torx Screwdriver The torx type of screw has the most surfaces to turn against and therefore has the greatest resistance to screw head damage. Needle-Nose Pliers They are great for grasping connectors or small screws when your hands are too big. IC Pullers It is usually made of spring steel and is shaped like letter U. At the ends of the U, it has fingers that are designed to be slipped between the chip and socket. Flashlight Another handy tool to have is a small flashlight especially when youre crawling around under a desk looking for a dropped screw or trying to find a particular component in a dark computer case. Compressed Air The best way to clean out the dust is with clean, dry, compressed air. Soldering Iron Traditionally used to connect electronic components to a circuit board. One tool that is used less and less in the computer service industry. Wire Cutter/Stripper Used to prepare wires for connection Multimeter Combination of several kinds of testing meters, including an ohmmeter, ammeter and voltmeter. It can help to detect the correct operation or failure of several different types of components.

Software Tools We can use software diagnostic programs to troubleshoot some hardware components. There are programs available for configuring hardware. There are also programs for testing the operation of other programs. Bootable Disks The very best software diagnostic tools for DOS machines are a bootable disk: a disk that has been formatted with a version of DOS and made bootable. Software Diagnostics Software tools that examine the hardware report its configuration and identity any errors it finds. Programs that serve mainly as reference materials.

ELECTROSTATIC DISCHARGE (ESD) It happens when two objects of dissimilar charge come in contact with one another. The two objects exchange electrons in order to standardize the electrostatic charge between them. This charge can, and often does, damage electronic components.

Antistatic Wrist Strap Often referred to as an ESD strap. It works by attaching one end to an earth ground and wrapping the other end around your wrist. This strap grounds you body and keep it at zero charge. Antistatic Bag are important tools to have at your disposal when servicing electronic components because they protect the sensitive electronic devices from stray static charges. ESD Static Mats Drains excess charge away from any item coming in contact with it. Are also sold as mouse/keyboard pads to prevent ESD charges from interfering with the operation of the computer.

THE PHYSICS OF ELECTRICITY What is Electricity? is a fundamental form of kinetic or potential energy created by the free or controlled movement of charged particles is the science, engineering, technology and physical phenomena associated with the presence and flow of electric charges Conductor vs Non-conductor (Insulator)Conductor materials allowing the flow of electric charge. is a material which contains movable electric charges.Insulator material that does not respond to an electric field and completely resists the flow of electric charge.

Dynamic vs Static Electricity

Dynamic Electricity involving or relating to energy and forces that produce motion

Static Electricity a stationary electric charge that builds up on an insulated object Electromagnetic TheoryElectromagnetism It is the unity of electric and magnetic phenomena. is the branch of science concerned with the forces that occur between electrically charged particles. In electromagnetic theory these forces are explained using electromagnetic fields. TRANSFER OF HEAT is a disciplined of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and heat between physical systems.

is classified into various mechanisms, such as heat conduction, convection and thermal radiation.

Conduction The transfer of energy between objects that are physical contact Convection The transfer of energy between an object and its environment, due to fluid motion Radiation The transfer of energy to or from a body by means of the emission or absorption of electromagnetic radiation.COMPUTER ELECTRONICS COMPONENTSANALOG VS. DIGITAL SIGNALS Signal is any kind of physical quantity that conveys information. a piece of information communicated by an action, gesture, or sign information transmitted by means of a modulated current or an electromagnetic wave and received by telephone, telegraph, radio, television, or radar. Analog Signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity. is a signal that can be continuously, or infinitely, varied to represent any small amount of change. Signals that change values over time. Digital Signal Is a physical signal that is a representation of a sequence of discrete values (a quantified discrete-time signal). it represents varying physical quantity such as sound or light waves by means of discrete signals interpreted as numbers, usually in the binary system, as in a digital recording or digital television. Signals that contain values that is discrete

RESISTORS a passive two terminal electrical component that implements electrical resistance as a circuit element It resists the flow of electricity a component of an electrical circuit that has resistance and is used to control the flow of electric current There are two types of resistors: fixed and variableFixed Resistors Are used when you need to reduce the current by a certain amount They are easily identified by their size and shape Their resistance level is indicated by means of colored bands painted on the resistors Variable Resistors It also called a rheostat or potentiometer (pots) It can be used to vary resistance directly from zero to infinity or it slowly vary from one source to anotherCapacitors is used to store electrical charges originally known as condenserVACUUM TUBES is a device controlling electronic current through a vacuum in a sealed container The grandfather/grandparent of todays computer componentsTRANSISTORS The parents of todays electronic computers is a semiconductor device used to amplify and switch electronic signals and powerToleranceNone - 20%Silver - 10%Gold - 5%

Standard Color Codes for ResistorsColor1st Band (Left)2nd Band (Right)3rd Band (Multiplier)

Black0010

Brown11100

Red221000

Orange3310000

Yellow44100000

Green551000000

Blue6610000000

Violet77100000000

Gray881000000000

White99N/A

II. Computer Hardware Architecture

SYSTEM BOARD AND COMPONENTS System Board The spine of the computer Also known as the motherboard It is the most important component in the computer because it is the component that connects all the other components of the PC together Types of System Board Integrated System Board most of the components that would otherwise be installed as expansion cards are integrated into the motherboard circuitry Non-Integrated System Board have each major assembly installed in the computer as expansion cardSystem Board Factors: AT-Style Motherboard (Advance Technology) is an older style of motherboard The processor, memory and expansion slots are in line with each other Its key features are a two-piece power supply connector, ribbon cables that connect the I/O ports to the board, and an AT-style keyboard connector. The expansion slots are parallel to the wide edge of the board Baby AT-Style Motherboard Because of advance in technology, the same number of components that were originally AT motherboard was compressed into a smaller area. This configuration is known as the baby AT configuration ATX-Style Motherboard (Advance Technology Extended) It provides many design improvements over the AT, including I/O ports built directly into the side of the motherboard, the CPU positioned so that the power supply fan helps cool it, and the ability for the PC to be turned on and off via software Micro ATX was released in 1997 for a smaller and typically cheaper systems. It has become popular in recent years in low-cost PCs. The maximum size of a micro ATX motherboard is 244mm square, compared to 305mm x 244mm for a standard ATX motherboard. The micro ATX is backward compatible with the ATX. NLX (New, Low profile Extended) this form factor is used in low-profile case types. It incorporates expansion slots that are placed on a riser board to accommodate the reduction in case size. However, this design adds another component to troubleshoot BTX (Balance Technology Extended) was design by Intel to deal with issues surrounding ATX (heat, power consumption, and so on). The BTX motherboard is larger than ATX, so there is more room for integrated components; there is also an optimized and a low-profile option

System Board Components The following components are found on a typical motherboardExpansion Slots the most visible part of any motherboard. They are used to install various devices in the computer to expand its capabilities ISA Expansion Slots - Integrated Standard Architecture they have easily recognize as they usually black and have two parts, a shorter and a larger part PCI Slots Peripheral Component Interconnect they are easily recognize as they are short (around 3 long) and usually white AGP Expansion Slots Accelerated Graphics Port are designed to be direct connection between the video circuit and the PCs memoryMemory Slots or Random Access Memory (RAM) are the next most profilic slots on a motherboard and they contain actual memory chips Single Inline Memory Module (SIMM) Dual Inline Memory Module (DIMM)Laptop memory comes in smaller form factors known as Small Outline DIMMs (SoDIMMs)CPU Slots and Socket it permits the attachment of the CPU to the motherboard, allowing the CPU to use the other component of the system PGA Socket (Pin Grid Array) In the past, the CPU slot was rectangular box called a PGA socket, with many small nodes to accommodate the pins on the bottom of the chip SECC (Single Edge Contact Card) The style of CPU slot includes Slot 1 and Slot 2 for Intel CPU Slot A for AMD CPUPower Connector - it allows the motherboard to be connected to the power supplyKeyboard and Mouse Connector Two main types: AT PS/2BIOS Chip (Basic Input / Output System) It is a special memory chip that contains the BIOS software that tells the processor how to interact with the rest of the hardware in the computer

On-Board Floppy and IDE - connectors drive interface Two primary types Floppy Drive Interface IDE Interface (Integrated Drive Electronics)

Peripheral Ports and Connectors Serial Port and Cable a serial port can be either 9 pins or 25 pins male connector USB Port and Cable (Universal Serial Bus) it is a standard interface that connects peripheral devices to a computer Parallel Port and Cable it is also called printer port (that can transmit 8 bits). It has a standard Type A 25-pin female connector Network Port and Cable also called RJ-45 port, connects a computer to a network. RJ Registered JackCMOS Battery (Complimentary Metal-Oxide Semiconductor) to prevent CMOS from losing its information, motherboard manufactured includes a small battery called CMOS battery. It displays the current date and time to the computerVIDEO PORTS Video Graphic Array (VGA) - has three-row 15 pin female connector and provides analog output to a monitor Digital Visual Interface (DVI) 24 or 29 pin female connector High Definition Multimedia Interface (HDMI) has a 19 pin connector and provides digital video and digital audio signalsMICROPROCESSOR: AN OVERVIEW Central Processing Unit (CPU) it controls and directs all activities of the computer using both external and internal bus CPU Manufacturers Motorola Advanced Micro Devices Cyrix IBM Intel

CPU ARCHITECTURE DIP (Dual Inline Package)

PGA (Pin Grid Array)

CPU Basic Structure Math Coprocessor - The math coprocessor is used to improve the processors number-crunching speed

Clock Speed - The clock speed is the frequency with which a processor executes instructions

Cache Memory - Storage area for frequently used data and instructions

The Bus The system boards under lying circuitry. A bus allows all devices to communicate with each other

External Bus (System Bus) It allows the processor to talk to another device Data Bus Used to send and receive data. The larger the bus width, the more data can be transmitted Address Bus The address bus also contains a set of wires to carry information in and out of the processor, but the information the address bus sends is addressing information used to describe memory location

The BIOS (Basic Input / Output System) Three major company that manufacture ROM BIOS software1. Phoenix Technology pioneer2. American Megatrends International (AMI)3. Award Software

Memory1. DRAM (Dynamic Random Access Memory) DRAM is dynamic random access memory. This is actually is RAM that most people are talking about when they mention RAM. When you expand the memory in a computer, you are adding DRAM chips.

2. SRAM (Static Random Access Memory The S in SRAM stands for static. Static random access memory doesnt require the refresh signal that DRAM does. The chips are more complex and are thus more expensive.

3. ROM (Read Only Memory) ROM stands for read-only memory. It is called read-only because it cant be written to. Once the information has been written to the ROM, it cant be changed. ROM is normally used to store the computers BIOS, because this information normally does not change.

4. CMOS (Complimentary Metal-Oxide Semiconductor) CMOS is a special kind of memory that holds the BIOS configuration settings. CMOS memory is powered by a small battery so the settings are retained when the computer is shut off.

5. Hard Disk System Hard disk reside inside the computer and can hold more information than other forms of storage. The hard disk system contains three critical components: the controller, the hard disk, and the host adapter

6. Floppy Drives A floppy disk drive is a magnetic storage medium that use a floppy diskette made of a thin plastic encased in a protective casing.

Floppy Diskette CapacitiesFloppy Drive SizeNumber of TracksCapacity

5 40360 KB

5 801.2 KB

3 80720 KB

3 801.44KB

3 802.88 KB

7. CD ROM Stands for Compact Disk Read Only Memory. Have been standardized across platforms with ISO 9660 standard. ISO International Organization for Standardization

8. DVD ROM Digital Versatile Disk

9. USB Flash DriveUniversal Serial Bus

MICROPROCESSOR PROGRESSION: INTEL AND AMD CPU EVOLUTION The Intel Family ProcessorsChipYear AddedData Bus Width (in bits)Address Bus Width (in bits)Speed (in MHz)TransistorsOther Specifications

808019748826,000Used only in an appliances

8086197816205-1029,000Internal bus ran at 8 bits

808819798204.7729,000

80286198216248-12134,000First to used PGA

80386DX1985323216-33275,000

80386SX1988162416-20275,000

80486DX1989323225-501.2 million8 KB of Level 1 Cache

80486SX1991323216-331.185 millionMath coprocessor disabled

80487SX1991323216-331.2 million

80486DX21991323233-662.0 million

80486DX41992323275-1002.5 million

Pentium1993323660-2003.0 millionSuperscalar

Pentium Pro19956436150-2005.5 millionDynamic execution

Pentium II19976436233-4507.5 million32 KB of Level 1 cache, dynamic execution and MMX technology

Pentium II Xeon19986436400-6007.5 millionMultiprocessor version of Pentium II

Celeron19996436400-6007.5 millionValue version of Pentium II

Pentium III19996436350-10009.5 million

Pentium III Xeon19996436350-10009.5 millionMultiprocessor version of Pentium III

Note :*Dual External (DX) *Single External (SX)

2 Types of Level of Cache Memory*Level 1 internal (SRAM) *Level 2 external (RAM)MMX Technology It includes 57 new instructions for better video, audio, and graphic capabilities It features Single Instruction Multiple Data (SIMD) technology, which enables one instruction to give instructions to several pieces of data rather than a single instruction per piece of data Its cache was doubled to 32 KB

Physical Appearance of PentiumClass ProcessorsProcessorSpeed (MHz)SocketPinsVoltageCache

Pentium-P560-6642735V16 KB

Pentium-P54C72-2005 or 7320 or 3213.3V16 KB

Pentium-P555C166-33373213.3V32 KB

Pentium-Pro150-20083872.5V32 KB

Pentium II233-450SECCN/A3.3V32 KB

Pentium III450-1130SECCN/A3.3V32 KB

AMD Processor and their Intel EquivalentCPUClock Speed (MHz)Intel EquivalentSocket/Slot Type

Am486X4100486DX4Socket 5

Am486DX4-120120486DX4Socket 5

Am5x8675Pentium over DriveSocket 5

K5 PR7575PentiumSocket 5





K5 PR166116.66PentiumSocket 5

K6-166166PentiumSocket 7

K6-200200Pentium IISocket 7

K6-233233Pentium IISocket 7

K6-II500-550Pentium IISocket 7

K6-III400-450Pentium IISocket 7

Cyrix Processors and their Intel EquipmentCPUClock Speed (MHz)Intel EquipmentSocket/Slot Type

6x86-PR120100PentiumSocket 7



6x86-PR166133Pentium IISocket 7

6x86-PR200150Pentium IISocket 7

6x86MX-PR166150Pentium IISocket 7



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