Computer Components

Lesson 1. Course Introduction

This course focuses on all types of computer components, including the power supply, motherboard, complementary metal-oxide semiconductor (CMOS), central processing unit (CPU), adapter card types, slot types, and display and input devices.
This course will also look at various types of ports and cables, cooling systems, hard disk drives, floppy disk drives, Random Access Memory (RAM), and AT and ATX motherboard form factors, and the installation and configuration of these devices.

Finally, this course will consider backup/restore procedures, basic troubleshooting techniques and preventive maintenance procedures.

Lesson 2. The Central Processing Lesson

A personal computer is an electronic device made up of several components that work together to perform a task. This device accepts numeric and textual data from a user, processes the data, and displays the result to the user. The manner in which the computer must process the data is specified by the user through a computer program.
After completing this lesson, you should be able to:

• Discuss the various components that make up a personal computer

A personal computer consists of several components connected to the motherboard. A computer may include the following components: power supply, motherboard, CMOS, CPU, IDE and IDE components, SATA, and adapter cards.

* Power Supply
The circuitry and various components that constitute a computer use electricity. A power supply provides the power needed to control all the components in a computer.
Three forms of power supply are used: Extended Technology (XT), Advanced Technology (AT), and Advanced Technology Extended (ATX).

A power supply unit is rated in watts.
The power supply unit transforms AC voltage from a wall socket — typically 110V AC — to the low DC voltage required by the circuitry and devices. The required voltages are +3.3V, +5V, -5V, +12V, and –12V.

* Motherboard
The motherboard is a large circuit board mounted within a system case. The motherboard contains a CPU, memory, and almost all of the support circuits that make up the computer. The specification of the motherboard determines the speed and capability of the computer, including:

• The speed and type of CPU that may be used in the computer.
• The speed and amount of memory that may be used in the computer.
• The number and nature of the expansion boards that may be used in the computer. Expansion boards modify or enhance the functionality of the motherboard.

There are two types of motherboards:

• Nonintegrated motherboards — These motherboards do not have built-in components. You have to install adapter cards separately, such as the video card, sound card, and display card.
• Integrated motherboards — These motherboards include pre-installed components, and you do not have to install or attach components separately. These motherboards are simpler and cheaper than nonintegrated motherboards. A major drawback of an integrated motherboard is that if any of the components fails, the entire motherboard must be replaced. These motherboards are cheaper initially but very expensive to repair.

* Complementary Metal-Oxide Semiconductor (CMOS)
The CMOS is an integrated chip that includes a microprocessor, microcontroller, static RAM, and other digital logic circuits. CMOS stores a configuration program that is invoked by pressing a key or a key combination such as Del, F2, Ctrl+Alt+Esc, or Esc during startup.
The CMOS configuration program includes a detailed menu leading to individual screens controlling groups of settings. The layout of the menu and the individual configuration screens vary with the version and make of the BIOS. The specific names for the settings also vary with BIOS versions.

* CMOS Configuration Settings
The following is a list of CMOS configuration settings located in the CMOS configuration program.
Default Settings
CPU Settings
Parallel Port Settings
Serial Port Settings
Floppy Drive Settings
Boot Settings
Hard Drive Settings
IDE Configuration Settings
Memory Settings
Time Settings
Setting Passwords
Plug-and-Play BIOS Settings
On-Board Device Settings
Virus Protection Setting
Power Management Setting
Upgrading BIOS

* Central Processing Unit (CPU)
The processor, also known as the CPU, functions as the brain of the computer. All operations in the computer occur under the control of the CPU.
In a computer, the CPU consists of a single chip, known as a microprocessor. A microprocessor is practically a computer on a chip — with only the main memory and Input/Output (I/O) devices being external to the microprocessor.
There are other components necessary in a functional computer. These other components take care of support functions such as adjusting the timing of signals, translating the voltage level of signals, and buffering signals. These support functions are provided by the chipset and other components on the motherboard.
Modern CPUs include various advanced technologies.

Hyper-threading
This technology was introduced by Intel in P4 microarchitecture. Hyper-threading Technology (HTT) allows processors to execute multiple instructions at the same time. An operating system assumes a processor to be two processors running in a computer and distributes the work between them. This allows multiple threads to run simultaneously.
Dual core
This technology is an enhancement of HTT. A dual core processor combines two processors into a single package. Dual core technology expands a computer's capabilities, and allows improved performance. Dual core processors are capable of performing multiple tasks such as playing games and downloading data from the Internet.
Throttling
CPU throttling is used to reduce CPU time for misbehaving applications. For example, if an application consumes 100 percent of the CPU time, a computer will become unresponsive. CPU throttling prevents such situations.

Micro code
Micro code is a program or set of instructions executed by a processor. Micro codes are also referred to as micro programs. Multimedia Extensions (MMX) is an example of a micro program used to execute a particular set of instructions.

Overclocking
Overclocking increases CPU clock speed and improves computer performance. Overclocking works on processors designed to run at overclocked speed. Overclocking also increases CPU heat levels, so you should use a special cooling mechanism to prevent the CPU from overheating.

Cache
Cache is a memory chip located on a CPU. Cache stores data and instructions to be processed by the CPU. The cache memory located on the CPU is referred to as L1 cache.

Voltage regulator module
The voltage regulator module (VRM) is a circuit that regulates the voltage level required by the CPU.

Speed
Speed refers to the clock speed of the CPU. The speed of the CPU is measured in Megahertz (MHz) or Gigahertz (GHz).

32-bit and 64-bit
The system bus used to process data between primary memory and the CPU can be 32-bit or 64-bit. More data can be processed at one time on a wider system bus.

* Integrated Drive Electronics (IDE) and IDE Components
IDE is a specification for disk drives and interfaces. An IDE drive contains a drive controller, which is electronic circuitry responsible for translating the storage requests issued by the CPU to the voltages that move the read/write heads of the drive. The drive communicates with the motherboard through a simple, low-cost interface, which may be integrated on the motherboard itself.

The early IDE specification evolved to Enhanced IDE (EIDE) and the AT Attachment 2 (ATA 2) specification. Current ATA specifications include ATA66, ATA100, and Serial ATA.
Although the original IDE specification is long obsolete, the term IDE is still in use and generally refers to the current ATA specifications.

The IDE/ATA 40-pin ribbon cable is used to connect IDE hard drives. An IDE ribbon cable has three connectors, usually blue, black, and grey in color.
The blue connector is used to connect to the motherboard and the black and grey connectors are used to connect IDE devices, which can be hard drives, CD-ROM drives, or DVD-ROM drives.

If two drives are connected to one IDE ribbon cable, one must be configured as master and the other as slave, or both should be configured as Cable-Select.
A single IDE bus cannot have two master or two slave IDE devices. When both drives on a single IDE bus are configured as master or slave, the computer will not be able to boot from either of the drives connected.
This orientation is typically specified by jumper caps and jumper pins. The default jumper setting for most IDE drives is either master or slave; however, some IDE drives are jumpered as Cable-Select. A Cable-Select setting means that the IDE cable location will determine whether the drive is a master or a slave.

Specification	Data throughput speed (Megabytes per second)	Number of IDE (ATA) channels per interface	Number of drives supported per channel	Cable type
IDE (corresponds to ATA)	Up to 3.3 MBps	1	2	40-pin ribbon cable
EIDE (corresponds to ATA 2)	Up to 16 MBps	2	4	40-pin ribbon cable
ATA 3	Up to 16 MBps	2	4	40-pin ribbon cable
ATA 33 (Ultra DMA 33)	Up to 33 MBps	2	4	40-pin ribbon cable (80-pin high density ribbon cable optional)
Ultra ATA 66	Up to 66 MBps	2	4	80-pin ribbon cable
Ultra ATA 100	Up to 100 Mbps	2	4	80-pin ribbon cable

* Serial Advanced Technology Attachment (SATA)
SATA is an enhancement to the Parallel ATA (PATA) standard. PATA is a hard drive interface for desktop PCs, laptops, and servers. PATA was replaced by SATA. SATA overcomes PATA problems such as signal timing and electromagnetic interference (EMI). SATA is fully compatible with PATA. SATA supports all commands, registers, and controls of PATA. SATA transfers data serially and allows the highest data throughput. Three modes of SATA standard are proposed. Two modes are currently available, and the third mode is likely to come soon. All modes use the same cable and connectors. The only difference between the three is data transfer speed.

Serial ATA Type	Signal Rate (Gbps)	Bus Speed (MHz)	Bandwidth (MBps)
SATA – 150	1.5	1500	150
SATA – 300	3.0	3000	300
SATA – 600	6.0	6000	600

Adapter cards, also known as add-on cards or expansion cards, are independent circuit boards that increase the functionality of a computer. Adapter cards are usually installed in Peripheral Component Interconnect (PCI) expansion slots.

Network interface card (NIC)
A NIC is installed in a PCI expansion slot on the motherboard. It's used to connect a computer to a network. In integrated motherboards, you do not have to install a NIC separately because the NIC is built in.

Sound card
A sound card, also called an audio card, is used to produce sound. It converts computer signals into sound. A typical sound card consists of ports such as a game port, line in port, line out port, and the microphone port. You can use the game port to connect joysticks to a computer, and a line in port to connect a cassette tape or record player. You can also connect speakers or headphones to a line out port.

Modem
A modem is used to connect a computer to a remote computer or to the Internet over a telephone line. It modulates and demodulates the signals.

Video card
A video card allows the computer to display information such as text, images, and videos on the monitor.

Riser card
A riser card is used to extend the motherboard to include extra expansion slots. Intel introduced these cards for ATX motherboards. You can install up to three PCI cards on a single riser card. The only disadvantage of using a riser card is that the remaining PCI slots on the motherboard cannot be used if a riser card is installed in any PCI slot on the motherboard. A riser card has audio, modem, and networking functionalities. A riser card contains a 22-pin connector so that it can be installed on one of the PCI slots on the motherboard.


* Identifying Adapter Cards
The important concepts are:

Network Interface card

This adapter card is installed in a PCI expansion slot on the motherboard; it's used to connect a computer to a network.

Sound card

This adapter card consists of ports such as a game port, line in port, line out port, and microphone port.

Modem

This adapter card is used to connect a computer to a remote computer or to the Internet over a telephone line.

Video card

This adapter card allows the computer to display information such as text, images, and videos, on the monitor.

Riser card

This adapter card is used to extend the motherboard to include extra expansion slots.

* Identifying Advanced Technologies
The important concepts are:

Hyper-threading

This technology was introduced by Intel in P4 microarchitecture. It allows processors to execute multiple instructions at the same time.

Dual core

This technology is an enhancement of HTT that combines two processors into a single package. This technology expands a computer's capabilities and allows improved performance.

Throttling

This technology is used to reduce CPU time for misbehaving applications; it prevents such applications from using 100 percent of the CPU time.

Micro code

This technology is a program or set of instructions executed by a processor.

Overclocking

This technology increases CPU clock speed and improves computer performance. It also increases CPU heat levels.

Topic 2.1 Exercises

* Exercise 1
Try identifying various components inside your computer case.
Please Note: Use an anti-static wrist strap to ground your body and keep it at zero charge, thus preventing static electricity charge.

Step	Action
1	Open the computer case.
2	Locate the power supply.
3	Locate the motherboard. Verify if it is an integrated or nonintegrated motherboard.
4	Locate the CPU.
5	Locate any IDE devices.
6	Seal the computer case.

In this lesson, you learned that a personal computer consists of several components connected to the motherboard. You learned about the power supply, motherboard, CMOS, CPU, IDE and IDE components, SATA, and adapter cards.

Lesson 3. Slot Types and Display Devices

Expansion slots, also known as connectors, are I/O slots on the motherboard into which adapter cards can be plugged. There are two types of display devices; the cathode ray tube and the liquid crystal display.
After completing this lesson, you should be able to:

• Discuss various types of expansion slots
• Explain the two types of display devices PCs use

* Slot Types
There are several different types of expansion slots that can be plugged into a computer's motherboard that will be discussed over the next few pages. Expansion slots are connected to the data and address buses of the CPU. They're often called the expansion bus.
Expansion slots adhere to mechanical and electrical standards, which provide compatibility for expansion cards from a variety of vendors.

* Industry Standard Architecture (ISA) Slot
ISA slots, though outdated, ensure compatibility with legacy cards such as network adapters and modems. IBM introduced the 16-bit ISA slot to run at 8.33 MHz in IBM AT 80286 computers. The 16-bit ISA bus requires a minimum of two cycles per transfer. The theoretical maximum transfer rate of a 16-bit ISA bus is 8.33 MBps.

* Extended ISA (EISA) Slot
The EISA slot is a 32-bit wide slot operating at 8.33 MHz. It's provided for backward compatibility with older ISA systems. The EISA bus has a bandwidth of about 32 MBps.

* PCI Slot
PCI is an enhancement of the legacy ISA standard. Compared to ISA, PCI devices are faster and smaller. PCI is available in two versions:

• PCI 2 offers a 32- or 64- bit bus with data transfer speeds of 132 or 264 MBps.
• PCI 2.1 has a 32- or 64-bit bus with data transfer speeds of 264 or 528 MBps.

PCI is the current industry standard; all motherboards provide PCI expansion slots.

* PCI Express (PCIe) Slot
PCIe is an enhancement to the original PCI that provides faster speed. PCIe transfers data at a speed of 250 MBps per lane. PCIe has a maximum of 32 lanes through which data is transferred.
* Accelerated Graphics Port (AGP) Slot
The need for AGP cards arose due to increasing demand for better graphics and faster video generation. An AGP video card provides improved performance unlike the legacy ISA or PCI cards. This card includes 3D video support. Pentium-based computers can directly communicate with AGP cards, providing higher-speed 3D graphics. Unlike other buses, AGP is used only for video cards.
The four modes of AGP are:

• AGP 1x, which uses a 32-bit bus that can transfer data at a maximum speed of 266 MBps.
• AGP 2x, which uses a 32-bit bus that can transfer data at a maximum speed of 533 MBps.
• AGP 4x, which uses a 32-bit bus that can transfer data at a maximum speed of 1066 MBps.
• AGP 8x, which uses a 32-bit bus that can transfer data at a maximum speed of 2133 MBps.

* Audio Modem Riser (AMR) Slot
AMR slots are designed by Intel to provide analog functionality. Riser cards are a type of AMR card. AMR slots are typically found on PIII and P4 motherboards, and they are not plug and play. An AMR slot consists of two rows of 23 pins.

* Communications and Networking Riser (CNR) Slot
CNR slots are commonly found in P4 computers. They're used to attach networking and telephony equipment to the computer. A CNR slot consists of two rows of 30 pins.

Note: CNR slot types aren't as common in modern computers.


* Universal Serial Bus (USB)
The USB standard allows you the ability to attach external peripherals to a computer. The USB 1.1 standard allows a maximum transfer rate of 12 Mbps. The newer USB 2.0 standard supports data transfers of up to 480 Mbps.
All USB cables have two wires that carry data and two wires that supply low-voltage power. The USB standard allows up to 127 devices to be attached to a single USB slot in a computer.

* Display Devices
There are two types of display devices that dominate the PC arena. Both types are known as monitors, but they use different technologies to create the image.

* Cathode Ray Tube
Cathode Ray Tube (otherwise known as CRT) monitors consist of an evacuated glass shell known as a tube. The screen is the front face of the shell. It's coated with dots of fluorescent material named phosphors. The phosphors emit light when hit by a stream of energized electrons. Three electron guns, one each for producing the colors red, green, and blue, shoot electrons at the phosphor. The beams are moved back and forth electronically in a constantly repeating pattern known as scanning the tube. The scanning of the tube causes the phosphors to glow and reproduce the data or the picture on the face of the tube.
CRT monitors have the following characteristics:

• CRTs are available in many sizes; the size of a CRT is measured diagonally from opposite corners.
• CRT displays are available in various resolutions, with resolutions of 1024 x 768 and 1280 x 1024 being very common. The monitor specification will indicate the maximum resolution you can use. A high-resolution monitor may be operated at a lower resolution.
• Each CRT display has a specific maximum scan frequency, which is the number of times the scan pattern of the electron beam is repeated every second. Common scan frequencies are 60 Hz, 70 Hz, 75 Hz, 85 Hz, 100 Hz, and higher. A higher scan frequency results in a steadier, more flicker-free picture. A monitor with high maximum scan frequency can be operated at a lower frequency.
• To improve the image quality on CRT monitors, you can use the V-Hold feature. You can also set the resolution and refresh rate. Typically, the default refresh rate for CRT monitors is 60 Hz.

* Liquid Crystal Display
Liquid Crystal Display (or LCD) monitors work by selectively rendering pixels opaque or transparent through an electrical signal. The LCD consists of a slim sandwich of glass and liquid crystal, with transistors integrated onto the glass. The transistors switch the pixels on or off rapidly. They're activated in a scan pattern across the screen. The scanning of the screen reproduces the data or the picture on the screen.
LCD monitors have the following characteristics:

• LCD monitors are available in many sizes. Portable computer LCD screens usually range between 12-15 inches in size.
• LCD displays are available in various resolutions, with resolutions of 1024x768 and 1280x1024 being common. The monitor specification will indicate the maximum resolution you can use.
• An LCD display is specified for a maximum scan frequency. This is the number of times the scan pattern of the transistors is repeated every second. Common scan frequencies are 60 Hz, 70 Hz, 75 Hz, 85 Hz, 100 Hz, and higher.
• LCD displays are smaller, lighter, and consume less power than CRT displays. CRT displays, however, can be brighter and exhibit higher contrast.

The dot pitch of a monitor is the distance between the phosphor dots on the monitor. The phosphor dots are actually in groups of three, for red, blue, and green phosphors.
Dot pitch is the distance between the groups of phosphors. The smaller the distance, the sharper the image. Typical the dot pitches available are 0.28 mm, 0.25 mm, and 0.21 mm.
Dot pitch can also refer to the distance between LCD cells, though it's mostly used with CRTs.

Different video technologies can be used in display devices to display images with maximum resolution.

Monochrome
Monochrome was the first video technology. It displays one color. This technology was used for operating systems such as Microsoft Disk Operating System (MS-DOS). IBM developed the Monochrome Display Adapter (MDA) card to display only text using a 720 x 350 pixels resolution.

Enhanced Graphics Adapter (EGA) and Color Graphics Adapter (CGA)
CGA was the first color video card developed by IBM. CGA was capable of displaying text as well as colors, but the graphics display was slow and provided only 320 x 200 resolution. However, the CGA displayed a better resolution of 640 x 350 with two colors, black and any other color. IBM also developed EGA that displayed 16 colors with a resolution of 320 x 200 or 640 x 350.

Video Graphics Array (VGA)
IBM developed the VGA card that has become the standard for color PC video. This video card has 256 KB video memory. It displays 16 colors at 640 x 480 pixels or 256 colors at 640 x 350 pixels.

Super VGA (SVGA)
IBM developed the VGA card, capable of displaying 16 colors at 640 x 480 pixels or 256 colors at 640 x 350 pixels. Other manufacturers set up the Video Electronics Standard Association (VESA) for video cards. This association introduced the Super VGA technology, which was an enhancement on existing technologies and has become the standard. It supports 256 colors at a resolution of 800 x 600 or 1,024 x 768 pixels with 16 colors. The SVGA connection uses a 15-pin connector for the video cable.

Advanced video interfaces increase the video quality of digital display devices.

Digital Visual Interface (DVI)
This interface was designed to provide high video quality. There are three different types of DVI connector: DVI-A — An analog-only connector. DVI-D — A digital-only connector with a 24-pin specification. DVI-I — A digital and analog connector with a 29-pin specification.

High-Definition Multimedia Interface (HDMI)
HDMI is a digital audio/video interface that includes all the functions of a DVI interface but provides higher resolution. HDMI acts as an interface between compatible digital audio/video sources such as a DVD player and a compatible video monitor. There are different types of HDMI connectors: Type A — An interface that uses a 19-pin connector. Type B — An interface that uses a 29-pin connector and provides higher resolution.

Separate (S-Video)
S-Video is an interface that uses analog video signals. S-Video combines two video signals into a single signal to provide high quality video. A typical S-Video connector has a 4-pin specification.

Component Video
Component video is a type of analog video used to carry separate signals. To provide high quality video, red, green, and blue colors are separately split on the source. Component video uses Radio Corporation of America (RCA) cables, such as the cable used to connect a DVD player to a television.


* Identifying Video Interfaces
The important concepts are:

Digital Visual Interface (DVI)

This interface was designed to provide high video quality. It can use an analog-only connector, a digital-only connector, or a digital/analog connector.

High-Definition Multimedia Interface (HDMI)

This interface can connect a digital audio/video source such as a DVD player and a compatible video monitor. It can use a 19-pin connector or a 29-pin connector for higher resolution.

Separate (S-Video)

This interface uses analog video signals, and combines two video signals into a single signal. It has a 4-pin specification.

Component Video

This interface is a type of analog video used to carry separate signals using RCA cables. To provide high quality video, red, green, and blue colors are separately split.

Topic 3.1 Exercises

* Exercise 1
Try identifying the types of display devices that are used in your work environment.

In this lesson, you learned that there are various types of expansion slots that can be used to attach adapter cards to your computer's motherboard, such as ISA, EISA, PCI, AGP, PCIe, AMR, CNR, and USB slots. Each of these slots fit their own type of adapter card.
You also learned that there are two types of display devices: Cathode Ray Tube (CRT) and Liquid Crystal Display (LCD). Each of these technologies provides a different way for an image to appear on a monitor.

Lesson 4. Input Devices, Ports, Cables, and Cooling Systems

Input devices are devices that are used for user input or user interaction. Connectors and ports are used to externally connect peripheral devices to a computer through cables. Cooling systems are used by computers to cool and remove heat from the internal components.
After completing this lesson, you should be able to:

• Discuss the various input devices employed for user interaction
• Explain the common types of connectors, ports, and cables used to connect peripheral devices
• Examine the different types of cooling systems used to cool internal computer components

* Input Devices
Devices that are used for user input or user interaction, such as keyboards, mice, bar code readers, multimedia devices, biometric devices, and touch screens, are input devices.

* Keyboard
A keyboard is the primary input device that helps a user interact with a computer. For example, in DOS-based applications the keyboard is the only component through which users can interact with the operating system.

* Mouse
Microsoft Windows introduced the first pointing device that was compatible with IBM computers. The mouse made it easy for a user to interact with the operating system.
You can connect the mouse with any PC using a serial, PS/2, or USB port. In addition, newer computers offer infrared technology that allows the use of wireless IrDA mice.

* Bar Code Reader
A bar code reader is a special input device used to read printed codes. This device is commonly used in retail stores to manage inventory. Bar code readers contain a light source that detects the codes. You can connect this device to a computer using a serial RS-232 port or USB port.

* Multimedia Devices
There are many types of multimedia input devices, such as Web and digital cameras, Musical Instrument Digital Interface (MIDI) devices, and microphones.
Web and digital cameras are used to capture digital videos and still images that can be transferred to a computer.
MIDI devices provide musical input used in audio mixing. Microphones are connected to a sound card and used to capture audio that can be stored on a computer.

* Biometric Devices
Biometric devices are used to recognize human physical characteristics such as fingerprints and the patterns found in the retina of the eye. Biometric devices forward the captured information to a computer which uses the stored information to authenticate a user.

* Touch Screen
Touch screens are monitors that both display and receive information. You can input data by touching the screen with your finger or with a stylus or pointer. For example, Personal Digital Assistants (PDAs) use touch screens. You do not have to use an input device such as a keyboard or mouse to input information.

* Ports and Connectors
A peripheral device is a device that is external to the computer. It connects to the computer through a cable that is plugged into a peripheral port. The cable connector is the primary means for identifying the port. All connectors used in peripheral ports are polarized or keyed. This means that a connector cannot be inserted the wrong way because the connector's shape allows it to be plugged in with only the correct orientation.

* Peripheral Ports
A peripheral port allows communication to peripheral devices by means of an I/O operation. A peripheral port on a computer has the following characteristics:

• A port has a type name such as serial, parallel, or USB.
• A port has a recognizable port connector. A port may use more than one type of connector if the port specification permits it.
• A peripheral port may transmit data in serial or parallel form. Serial transmission occurs over two wires, a signal wire and a ground wire, while parallel transmission occurs over multiple wires, usually 8 or 16 signal wires and a ground wire.

There are various common types of ports.

Serial port
This is one of the oldest types of ports. The serial port uses serial transmission. It is a slow port, and is used for connecting mice and modems where high speeds are not required. The serial port uses either a DB-9 connector or a DB-25 connector.

Parallel port
The parallel port, sometimes called the printer port, transfers eight bits at a time in parallel on eight signal pins and a ground pin, which makes it faster than a serial port. This port is traditionally used for printers, although modern printers are shifting to the USB port. The Enhanced Capability Port (ECP) and Enhanced Parallel Port (EPP) are improved and faster versions of the parallel port. In addition to transmitting data to external devices, both of these ports allow data to be sent back to the computer — they are bidirectional ports. ECP is the faster of the two.

USB port
A USB port is a high-speed serial-transmission port that offers hot plug functionality. The USB port uses a four-pin flat connector. The greatest distance allowed between a USB 1.1 device and the computer port is three meters. USB 2.0 allows up to five meters between the computer port and devices, but all devices must be 2.0 compliant. The USB port on the computer uses a 4-pin flat connector.

IEEE 1394/FireWire port
The IEEE 1394/FireWire port is an extremely high-speed serial-transmission port that allows devices to be hot plugged. Theoretically up to 64 devices can be daisy-chained together, each device connecting to the previous device with only the first device connected directly to the port. The high data transfer rate make this the port of choice for transferring digital image files.

There are also various common port connectors.

Registered Jack-11 (RJ-11)
These connectors are the standard connector for telephone connections, connections between two pairs of Unshielded Twisted Pair (UTP) wiring and a voice-grade telephone system. An RJ-11 connector consists of four wires that create a connection between a telephone-line jack and an analog modem.

Registered Jack-45 (RJ-45)
These connectors are similar to RJ-11 connectors, but are larger. An RJ-45 connector can connect both UTP and Shielded Twisted Pair (STP) cables to hubs, NICs, and various other twisted-pair networking devices. An RJ-45 connector consists of eight wires in four pairs, as compared to only four wires in RJ-11 connectors.

PS/2 and Mini-DIN port
A PS/2 connector, also known as a mini DIN connector, is a round connector with six pins. Older keyboards and mice use this connector. The keyboard and mouse PS/2 connectors are mechanically identical but electrically unique. Although it is possible to plug a keyboard or mouse into the wrong port, the device will not work unless it is plugged into its unique connector.

Centronics
This connector is used to connect parallel printers to a computer. This port is typically found on peripherals and not on computers.


The RS-232 standard issued by the Electronic Industry Association provides specifications for serial data transfers.
USB and IEEE 1394, also known as FireWire, are the newest standards for serial data transfers. Both standards support faster rates for data transfers than the older serial ports with RS-232 interfaces.
Because USB, FireWire, and RS-232 are serial protocols, they all transfer data one bit at a time.

The cable that connects peripheral equipment to the computer port typically have connectors at each end.

Serial cable
A serial cable uses DB 9 and DB 25 male and female connectors.

Null modem cable
A null modem cable is a serial cable that has a female plug at either end. The cable connects two computers through their serial ports. This allows the computers to communicate as if they were connected using modems.

Parallel cable
A parallel cable uses a DB 25 male connector at the computer end and a DB 25 female connector or a 36-pin Centronics connector at the other end.

USB cable
A USB cable usually has a flat rectangular A connector at the computer end and a square B connector at the device end. Some cables have an A connector at each end.


* Cooling Systems
Electronic components heat up quickly, and high temperatures can damage the components. Therefore, it is important to use proper cooling systems to cool and remove heat from a computer's internal components. The next few pages will discuss various methods of cooling.

* Fans
A fan is used to keep the CPU and power supply cool by providing airflow within a computer.
A desktop computer has few fans inside, but server computers come with many built-in fans. These may include the CPU fan, power supply fan, exhaust fan, and chipset fan. The main components that use air-cooling are the memory, CPU, and hard drive.
Some new cooling methods have been introduced, such as liquid cooling and Peltier cooling. However, these methods are risky and can damage your computer.

* Liquid Cooling
In a liquid cooling system water is circulated over the components. A water block is used to remove heat from the components and keep them cool. Water circulates through the block where it is cooled. Liquid cooling is not noisy, unlike air-cooling systems. Liquid cooling uses only one fan for cooling the water block. Liquid cooling is more expensive than air-cooling systems.

Heat pipes are another a liquid cooling method. A heat pipe is a hollow tube that contains a small quantity of cooling liquid used to transfer heat from computer components. Heat pipes are used as a thermal conductor to prevent a computer from heating.

* Heatsinks
Heatsinks prevent the CPU from overheating by pulling heat from it to keep it cool. A heatsink absorbs heat from the top surface of the CPU and allows this heat to dissipate from a much larger area — the surface area of the heatsink. Using a large heatsink improves the efficiency of cooling.
A thermal compound smeared on the top surface of the CPU improves heat transfer from the CPU to the heatsink. Heatsinks also have tiny fans to get rid of the heat.

* Peltier Cooling Devices
A Peltier cooling device transfers heat from one side of the device to the other. The cool side is towards the CPU and other components, and the other side is towards a heatsink or water block.

* Identifying Common Port Types
The important concepts are:

Serial port

This is one of the oldest types of ports. This port on the computer uses either a DB-9 connector or a DB-25 connector.

Parallel port

This port transfers eight bits at a time on eight signal pins and a ground pin.

USB port

This port is a high-speed serial-transmission port that offers hot plug functionality. This port on the computer uses a four-pin flat connector.

IEEE 1394/FireWire port

This port is an extremely high-speed serial-transmission port that allows devices to be hot plugged. Theoretically up to 64 devices can be daisy chained together.

* Identifying Common Cable Types
The important concepts are:

Parallel cable

This cable uses a DB 25 male connector at the computer end and a DB 25 female connector or a 36-pin Centronics connector at the other end.

Serial cable

This cable uses DB 9 and DB 25 male and female connectors.

USB cable

This cable usually has a flat rectangular A connector at the computer end and a square B connector at the device end. Some cables have an A connector at each end.

Null modem cable

This cable is a serial cable that has a female plug at either end of the cable and connects two computers through their serial ports.

Topic 4.1 Exercises

* Exercise 1
Try identifying the type of cooling system your computer system uses.
Please Note: Use an anti-static wrist strap to ground your body and keep it at zero charge, thus preventing static electricity charge.

Step	Action
1	Open the computer case.
2	Locate the CPU.
3	Identify the type of cooling that is being used.
4	Seal the computer case.

In this lesson, you learned that input devices such as keyboards, mice, bar code readers, multimedia devices, biometric devices, and touch screens can be used for user input and user interaction.
You also learned that peripheral devices external to the computer can be connected via a cable that's plugged into a peripheral port on the computer.
Finally, you learned that different types of cooling devices are designed to keep the computer's internal components cool and prevent damage from high temperatures generated by the components.

Lesson 5. Storage Devices

Storage devices store data and come in many types.
After completing this lesson, you should be able to:

• Discuss the various types of storage devices

There are various types of storage devices, such as a hard disk drive, floppy disk drive, Random Access Memory (RAM), CD-ROM, and Secure Digital (SD) card. These devices differ in terms of capacity, access time, and physical type of media.

* Hard Disk Drive
Hard disks are the most widely used secondary storage devices. Hard disks offer large, reliable storage capacities at a low cost-per-bit of storage.
Hard disk devices are used for permanent storage of data. Unlike RAM where data is only available while the computer is on, data stored on the hard disk remains even when the computer power is off.

A hard disk drive has disk-shaped platters that are used to store data. These platters are made of a light weight aluminum alloy that provides strength. A hard disk drive has one read/write head for each platter surface, one for the top and the other for the bottom side of the platter. The spindle motor used to spin the platters is located around the platters to help them rotate and control their speed. The platters rotate at a maximum speed of 15,000 rotations per minute.
The Master Boot Record (MBR) is located on the hard disk drive. It's stored on the first sector, called sector zero, of a hard disk drive partition. Typically less than 3% of the hard disk space is allocated to the MBR, which generally occupies about 512 bytes of hard disk space.

* Floppy Disk Drive
A floppy drive is a storage medium used to read/write data on a floppy disk. A floppy is a small diskette made of a thin magnetic disk, making it easy to transfer data from one computer to another. Compared to a hard disk that stores gigabits of information, a floppy disk has a limited capacity.

* Random Access Memory (RAM)
Computer memory holds data and instructions for the CPU. RAM consists of semiconductor chips, and is emptied when power to the chip is turned off. RAM is measured in megabytes. It is available in different size memory modules, with 32 MB, 64 MB, 128 MB, 256 MB, 512 MB, and 1 GB, being the most commonly-used sizes.

Memory modules are available in two types: parity and non-parity. Non-parity memory modules are normal modules that have one bit for each bit of data stored.
Parity memory modules have one extra bit for each byte of information stored. One byte uses 8 bits to store information. Parity modules are better because they have one extra bit per byte; they use that extra bit for error detection and correction.

Error Checking and Correcting (ECC) memory modules have become popular. ECC memory modules generate check bits stored with the data in memory.

Single-sided memory modules have memory chips on one side of the memory module. Double-sided memory modules have memory chips on both sides.
The two classes of RAM are:

• Static RAM (SRAM) — This type of RAM is fast but expensive. It is usually reserved for use as cache memory on a motherboard. Some amount of static cache RAM is provided within the processor chip itself. The battery-backed CMOS static RAM within the real time clock (RTC) chip allows the RTC to retain its contents even when the main power is turned off.
• Dynamic RAM (DRAM) — This type of RAM is slower than static RAM but faster than ROM. Dynamic RAM is used as main memory in computers because it is cheaper than SRAM. Sub-types of DRAM include Extended Data Output (EDO) RAM, Synchronous Dynamic RAM (SDRAM), and Double Data Rate (DDR) RAM. DDR RAM is the current standard.

DDR RAM is considered better than SDRAM because it provides double the transfer rate.

Type	Memory Speed	Symbol	DIMM Module
DDR 1600	200 MHz	PC-1600	184-Pin
DDR 2100	266 MHz	PC-2100	184-Pin
DDR 2700	333 MHz	PC-2700	184-Pin
DDR 3000	366 MHz	PC-3000	184-Pin
DDR 3200	400 MHz	PC-3200	184-Pin
DDR 3500	433 MHz	PC-3500	184-Pin
DDR 3700	466 MHz	PC-3700	184-Pin
DDR 4000	500 MHz	PC-4000	184-Pin
DDR 4200	533 MHz	PC-4200	184-Pin
DDR 4500	566 MHz	PC-4500	184-Pin

* Compact Disk-Read Only Memory (CD-ROM)
CD-ROMs are an optical read-only storage medium designed to hold up to 700 MB of data. CD-ROM drives have fast data transfer speed, and the disks are a reliable storage medium.
The CD-ROM transfer rate depends on its drive speed. A CD-ROM drive with 1x speed provides a data transfer rate of 150 Kbps. Drives with 8x speed have a data transfer rate of 1.2 Mbps. CD-ROM drives are available with a maximum 52x drive speed.

A CD-ROM drive consists of several components that help the drive to operate.

Laser diode
Gives off a low-energy laser beam toward a reflecting mirror.

Servo motor
Positions the laser beam onto the correct track of the CD-ROM.

Head actuator
Moves across the CD-ROM causing it to rotate and is part of the head assembly.

Beam splitter
Directs returning laser light toward another focusing lens.

Photo detector
Converts light into electric pulses.


* Secure Digital (SD) Card
An SD card is a flash memory technology used to store information. SD cards were first used in digital photography and are now used in notebook PCs and desktop computers. You can use a card reader device for read/write operations on an SD card. These devices are typically integrated into laptops. You can purchase this device if you have a desktop computer, attach it to a USB interface, and use it to store any type of information on.

* Identifying CD-ROM Components
The important concepts are:

Laser diode

Gives off a low-energy laser beam toward a reflecting mirror.

Servo motor

Positions the laser beam onto the correct track on the CD-ROM.

Head actuator

Moves across the CD-ROM causing it to rotate and is part of the head assembly.

Beam splitter

Directs returning laser light toward another focusing lens.

Photo detector

Converts light into electric pulses.

Topic 5.1 Exercises

* Exercise 1
Try identifying the various storage devices present inside your computer case.
Please Note: Use an anti-static wrist strap to ground your body and keep it at zero charge, thus preventing static electricity charge.

Step	Action
1	Open the computer case.
2	Locate the hard disk drive.
3	Locate the RAM.
4	Locate any other storage devices that might be present.
5	Seal the computer case.

In this lesson, you learned that there are various types of storage devices, such as a hard disk drive, floppy disk drive, Random Access Memory (RAM), CD-ROM, and Secure Digital (SD) card. These devices differ in terms of capacity, access time, and physical type of media.

Lesson 6. Installing and Configuring Computer Components

There are several common motherboard form factors that are used in modern computers. Two important motherboard form factors are AT and ATX.
After completing this lesson, you should be able to:

• Discuss the common types of motherboard form factors
• Install and upgrade personal computer components

* Motherboard Form Factors
Motherboards conform to physical and electrical specifications indicated by the form factor of the motherboard. The important form factors are Baby AT, AT, ATX, BTX, Micro ATX, and New Low Profile Extended (NLX). Both the AT and the ATX motherboard form factors support PCI and ISA expansion slots.

* Baby AT
The Baby AT motherboard form factor is the compressed form of the full AT form factor that was first introduced by IBM. Baby AT has a pair of 6-wire power connectors known as P8 and P9. When you plug the P8 and P9 connectors into a Baby AT motherboard, the black wires of P8 and P9 must be adjacent. If the connectors are plugged in the wrong way, then the motherboard can be permanently damaged.
In the Baby AT, only the keyboard port connector is soldered to the motherboard. All other ports are available as pin headers on the motherboard, connected through cables inside the system unit to port connectors at the back of the case.

* ATX
The ATX motherboard form factor has been universally adopted by most computer manufacturers. ATX has the features of the Baby AT and Low Profile Extended (LPX) motherboard form factors. The CPU and memory are relocated in ATX to allow more efficient cooling.
The power supply connector to the motherboard in ATX is a single 20-pin connector. This eliminates the P8 and P9 connectors' shortcoming because the ATX power supply connector cannot be plugged the wrong way. I/O port connectors are soldered to the motherboard in ATX. The ATX system case exposes the port connectors so that cables can directly plug in. Internal cables are eliminated in ATX.

* Balance Technology Extended (BTX)
BTX is a motherboard form factor proposed by Intel for PC motherboards. BTX was originally lined up as a replacement for the ATX motherboard form factor. BTX was designed to minimize problems that arose from using newer technologies that often required more power and created more heat on motherboards compliant with the circa-1996 ATX specification.

* Micro ATX
Intel developed Micro ATX with a small size specification. Micro ATX form factors define boards that are physically smaller than standard ATX. Micro ATX has fewer expansion slots than standard ATX.

* New Low Profile Extended (NLX)
NLX is a motherboard form factor designed for horizontal low profile desktop system cases. The NLX motherboard has an edge connector along one side that plugs into a riser card. All connections normally established with the motherboard are established with the riser card. The motherboard contains memory slots and a CPU socket, but no expansion slots.

* Hard Disk Drive
An IDE/ATA hard disk drive is installed on IDE controllers on the motherboard. The IDE/ATA interface uses channels to carry information between IDE devices. Each motherboard has two built-in IDE controllers: the primary IDE controller and the secondary IDE controller.
Each IDE controller on the motherboard is capable of supporting two devices, one configured as master and one configured as slave. A single IDE data cable connects both of the devices. Typically, the first disk, usually the disk with the operating system, is the master disk on the primary controller.

A hard disk can have four modes, set using jumpers. This orientation is specified by means of jumper caps and jumper pins. You can arrange the jumpers to configure the hard disk in the following modes:

• Single disk only
• Master disk
• Slave disk
• Cable select

When you add a second hard disk, the jumper settings on both disks must be configured appropriately. The interface is compatible with hard disk drives, CD-ROM drives, and other drives.

If two drives are connected to one IDE cable, the drives must be configured as master, slave, or cable-Select.
The default jumper setting for most IDE drives is either master or single, but some IDE drives are jumpered as cable select.
The cable select setting indicates that the IDE cable location will determine whether the drive is a master or a slave. If the drive is to be the only one on the channel, the jumper must be set to master.

Note: When installing a second hard disk drive on a computer, you should verify that all cables are connected properly and that the drive has the correct jumper settings. If your system BIOS is not configured to detect a second hard disk drive, manually configure the second drive in the BIOS.


* Disk Preparation
To install an operating system on a hard disk, you should first prepare the disk. The disk preparation procedure involves the following steps:

• Create partitions using the FDISK command-line utility. The first partition should be a primary partition.
• Format the partition using the FORMAT command. For example, to format Drive C type FORMAT C: at the command prompt. The FORMAT command supports only FAT16 and FAT32 file systems and cannot format a partition with the NTFS file system.
• Run the installation CD-ROM for the version of Windows you want to install.

Note: You can also create partitions and format hard disks from the Windows XP installation CD-ROM. During installation Windows XP setup prompts you to create and format partitions.


* Drive Imaging
If you want to install the Windows XP operating system on several computers with the same hardware configuration, you can use drive imaging, also known as disk duplication. The Windows XP operating system provides the System Preparation Tool, sysprep.exe, to prepare a computer for the creation of master images of an existing Windows XP system. Once the master image is created, the system's unique information, such as the computer name and Security Identifier (SSID), are removed so that this unique information is not included in the master image. This image can be distributed among other computers on which you want to install Windows XP.

After preparing a computer with the System Preparation tool, you should use third-party software such as Norton Ghost to create a disk or drive image. Windows XP does not include any tools for the creation of drive images.

* CPU
To install the CPU in a computer, use the following procedure:

Step	Action
1	Ensure that the CPU is compatible with the motherboard. You can use the motherboard documentation to check for compatibility.
2	Take electrostatic discharge (ESD) precautions and open the system case. Locate the old CPU.
3	Detach the heatsink. Locate the release lever on the Zero Insertion Force (ZIF) socket. Pull it away from the lock and flip it up. Remove the old CPU.
4	Remove the new CPU from its packaging, and insert it into the socket. Make sure the orientation is correct — the CPU should slip into the socket without you having to force it. Flip down the release lever and lock it.
5	Fit the heatsink on the new CPU.
6	Attach any cables or devices to the computer.
7	Seal the system case, attach all external cables, and restart the computer. You may have to run the BIOS setup utility to configure the CPU parameters in CMOS.

* External Storage
External storage devices are connected externally to the motherboard. They provide storage to the computer in addition to the storage already available on the internal hard disk. As a normal practice the external storage devices are used for backup purposes. Also, external devices are usually portable.

External storage drives come in different sizes in terms of storage space. At present, external storage devices come with size capacities from 20 GB to 300 GB.
Most external storage devices connect to the computer using either a FireWire cable or a USB cable. If an external storage device is connecting to the computer using a FireWire cable, it will require a FireWire interface card inside the system unit.

There are various external storage devices available.

Hard drives
Numerous types and sizes of hard disks are available, such as USB hard disk drives that attach to the USB interface on a computer.

CD-ROM drives and CD-RW drives
Each CD-ROM can hold up to 700 MB of data on a single disc.

DVD-RW drives
Each DVD can store up to 4.7 GB on a single optical disk.

Digital Audio Tape (DAT) drives
Each DAT tape stores from 12 to 20 GB on a single tape cartridge.

Digital Linear Tape (DLT) drives
Each DLT tape can be used to store more than 70 GB per tape cartridge.

ZIP drives
Each ZIP disk can store between 100 MB and 250 MB on a single disk.

Floppy drives
Each floppy disk can store up to 1.44 MB.

Flash drives
Even the least expensive flash drive can hold the data of many floppy disks. Many can store more data than a CD. Some can hold more data than a DVD.


* Display Devices
To connect a video adapter card or AGP card (or Accelerated Graphics port card used only for video), use the following procedure:

Step	Action
1	Power off the computer and disconnect all cables from the system case.
2	Take ESD precautions, and open the system case.
3	Locate an unused expansion slot compatible with the adapter card that you are installing or remove the old video card.
4	Unscrew and remove the slot cover. Save the screw to secure the new card.
5	If required, set the configuration jumpers on the card. Push the video adapter card or AGP card into the slot, and seat it down firmly.
6	Secure the video adapter card or AGP card with a screw.
7	Seal the system case, reattach all external cables, and restart the computer. Typically, the operating system will recognize the adapter and load drivers automatically. In some cases, you may have to run a vendor-supplied utility to install drivers.

* Input Devices
The following input devices plug into standard input port connectors:

• Mouse — Plug the connector from the mouse into the serial port, the PS/2 mouse port, or the USB port, depending on the type of mouse available.
• Keyboard — Plug the connector from the keyboard into the PS/2 port or the USB port, depending on the keyboard available.

* Multimedia Devices
Most computers are equipped with a sound card and a CD-ROM. Personal computers that have these multimedia devices are known as multimedia computers.

* Sound Card
Sound cards were originally installed separately on the motherboard. In modern computers the sound card is a built-in feature. Therefore, you do not have to install sound cards separately on a newer computer.
A sound card converts computer signals into sound. It can be used to connect speakers, microphones, and headphones, and it will help improve the overall sound quality of a computer.

To install a sound card in a computer that does not have built-in sound, insert the card in any empty PCI slot on the motherboard. After you have attached the sound card to the motherboard, you must install the card's drivers.
You can use the Device Manager to install a sound card driver. Driver media is shipped with the sound card, or you can download a sound card driver from the vendor's Web site. In the case of Plug-and-Play sound cards, Windows will automatically detect the new card and attempt to install the device driver.

Topic 6.1 Exercises

* Exercise 1
Try installing a new CPU into your computer.
Please Note: For the exercises in this course, you should set up a standalone system for practice. Do not use your production system for these practice exercises.

Step	Action
1	Ensure that the CPU is compatible with the computer's motherboard.
2	Take electrostatic discharge (ESD) precautions and open the system case.
3	Locate the CPU.
4	Detach the heatsink from the old CPU.
5	Remove the old CPU.
6	Insert the new CPU into the socket and lock it in.
7	Fit the heatsink on the new CPU.
8	Attach any cables or devices to the computer.
9	Close the system case and attach any external components.
10	Restart the computer. Note: You may need to run the BIOS setup utility to configure the CPU parameters in CMOS.

In this lesson, you learned that the important motherboard form factors are Baby AT, ATX, Micro ATX, and New Low Profile Extended (NLX).
You also learned how to install and upgrade the various types of components that make up a personal computer.

Lesson 7. Troubleshooting Computer Components

Troubleshooting is a skill that requires a good technical knowledge of both hardware and software. Every technician diagnoses and rectifies problems in their own way. The key concept behind troubleshooting is to troubleshoot a problem in the quickest and easiest way.
After completing this lesson, you should be able to:

• Identify tools, diagnostic procedures, and troubleshooting techniques for computer components

* Before You Start Troubleshooing
You should back up data before troubleshooting or replacing computer components. Crucial data should be backed up regularly to reduce the chances of data loss. A backup is a copy of data that can be restored in case of system failure. You can use the Microsoft Windows Backup utility to perform a data backup.To ensure a quality backup, you should verify that the data matches the original data. To restore the data previously backed up, you can also use the Microsoft Windows Backup utility.

* Troubleshooting Hardware and Software Problems
To troubleshoot a hardware or software problem, you need to observe the symptoms of the problem or have the symptoms reported to you. The steps that you take to rectify the problem will depend on the symptoms. In the case of symptoms being reported, you need to solicit more information to get a more accurate picture of the problem.

Here's a troubleshooting approach you can adopt:

• Perform a backup to avoid data loss before troubleshooting the problem.
• Assess the problem systematically and divide larger problems into smaller elements for analyzing individually.
• Check for common issues. Sometimes the problem is simple, but technicians overlook common issues because they assume they are not the cause of the problem.
• Try simple solutions first: ensure that devices are powered on and that cables are plugged in correctly. Move to more complex solutions after the simple solutions have been checked.
• Test potentially faulty devices one by one. The aim is to identify the device as faulty or eliminate it from the list of potentially faulty devices.
• Replace a defective device. Test the computer to ensure that the problem is resolved completely.

Note: When you replace computer components, you should first unplug the computer. Do not open a computer's case when it is powered on and the cables are plugged in.


* Identifying Troubleshooting Techniques
Before you troubleshoot a problem, you must prepare a plan, which includes defining the problem, creating a checklist of hardware components, identifying the type of problem the user is facing, and determining whether the problem is a hardware or software issue.

* Defining the Problem
Define a problem before you troubleshoot it. Ask the following questions:

• What problem is the user facing?
• How long has the user been facing the problem?
• Has the user installed any new software?
• Has the user installed any new hardware?

Getting answers to these questions will enable you to identify the problem.

* Reviewing the Checklist and Checking for Common Issues
After you have defined a problem, start the troubleshooting process. First find out whether the hardware components are functioning properly. You can achieve this by reviewing the components in your checklist. You can also prepare a second checklist by defining the functions of the computer, such as the booting sequence, printing, and running an application.

Troubleshooting a problem becomes easy if you first check for common issues. Make sure that all the cables are connected at both ends. Check whether the LEDs glow when the computer is turned on. Make sure that chips and connectors are not loose.

* Error Codes
Technicians can resolve many problems through error codes. The following types of errors occur during the boot process:

• Beep error codes — Normally a beep occurs when you turn on a computer. However, when a series of beeps occur, it indicates a component failure. Usually a beep error indicates that there is RAM failure, but there are other components that might cause it as well.
• On-screen error codes — On-screen errors are generated when any component is not functioning properly. These errors are often expressed as hexadecimal numbers. For example, you may notice a Press F1.T> message on the screen, which is a keyboard error.

* Identifying the Problem as Hardware- or Software-Related
Hardware problems are easier to resolve than software problems. The key is to determine the type of problem. If it is a hardware problem, identify the component that has failed. For example, you can easily replace a NIC if you identify it as the problem.
Software problems require more effort to diagnose. Sometimes a simple restart solves the problem. You need a lot of experience to resolve these problems quickly and efficiently.

* Diagnostic Packages
Diagnostic packages are available for testing major computer components. Some packages are freely available on the Internet. These diagnostic packages perform necessary tests and provide status information for the components. This information is helpful when diagnosing a problem. Tests are performed mainly on the memory, processor, display, and hard drive.

Note: You can run diagnostic packages from a 3½" floppy disk or CD-ROM when your system is not booting up.


Various tools are available to diagnose hardware problems.

Screwdriver
Computer cases as well as the components installed in the computer are connected using screws. To replace a component, you must have a screwdriver kit. The three types of screwdrivers are flat-blade screwdrivers, torx screwdrivers, and Philips screwdrivers.

Plastic tweezers
Plastic tweezers are a handy tool used for picking up tiny screws that fall on the motherboard. This tool is useful when working in tight places.

Flashlight
This device is used for finding dropped screws that are not visible in a dark computer case.

Multimeter
This is an electronic troubleshooting device that comes in analog and digital forms. It measures electric pulses of voltage. The digital version is known as a Digital Multimeter (DMM). You can use this device to check transistors, capacitors, diodes, and coils. A multimeter also has advanced capabilities, but DMMs that include these features are expensive.


* Troubleshooting Personal Computer Components
As a technician, you should be aware of common hardware problems. To troubleshoot hardware problems easily and efficiently, you must have extensive hands-on experience.

* Power Supply Problems
The most probable cause of a dead system is the power supply. The power supply is the only source of power to the computer other than the CMOS battery, which supplies only enough power to maintain the CMOS settings.
If the power supply is not working, the best option is to dispose of the power supply and replace it. It is cheaper to buy a new power supply than to repair one. Before replacing a power supply, you should check the voltage information on the power supply's label and obtain a new one with the same voltage.

* CPU Problems
If you replace a CPU and the Power-On Self Test (POST) fails to correctly identify it, the most likely cause of the problem is an old BIOS. You should check with the manufacturer to see if this is indeed the problem, and then update the BIOS. Flashing the BIOS is the term for replacing its firmware. Flashing the BIOS is also used to upgrade the motherboard's firmware.
Misconfigured jumpers can be another cause of a misidentified processor in older motherboards.
CPU overheating is a common problem that may cause a computer to reboot automatically. To prevent a CPU from overheating, you can use thermal grease and heatsinks.

* Motherboard Problems
Typically, a motherboard problem results in the computer being unable to boot. Alternatively, a motherboard defect may result in I/O problems where a device connected with the motherboard malfunctions.
If there is no display but the power indicator LED is on, and there is no beep code, then you should suspect a motherboard fault. If the motherboard is faulty, you should replace it with a working motherboard.

The CMOS RAM on the motherboard, backed up by a small battery, holds configuration information for the computer. If the battery fails or is temporarily removed, the CMOS will lose its settings. If the configuration information is erased or altered at every shutdown, you should suspect a weak or exhausted CMOS battery.

Note: If you need to remove the BIOS password, you can remove and re-insert the battery. This helps clear the existing settings of the BIOS. If removing and re-inserting the battery does not resolve the BIOS errors, you should also check the jumper settings. Some motherboards support changing CMOS jumper settings to clear the BIOS passwords.


* Display Problems
The common video problems that technicians face are that nothing appears on the screen or the video quality is not good. A blank screen results when the monitor power is off or the user has turned down the brightness. Technicians often overlook these common problems.

Monitor adjustment, loose or damaged cables, or incorrect display drivers may cause video problems. Perform the following steps to identify common display device problems:

Step	Action
1	Check that the video adapter is properly inserted in the expansion slot.
2	Check that the display cable and power cable are connected properly.
3	If the computer displays an image during boot but cannot load Windows, try reinstalling the display driver.
4	Check the display settings. Sometimes the configured resolution is the problem. Try lowering the resolution.
5	If you still face display problems after going through these steps, replace the video card.

For a monitor that doesn't work, use the following procedure:

Step	Action
1	Ensure that the monitor is plugged in correctly and that it's turned on. If the power indicator does not turn on, send the monitor for repair.
2	Turn the brightness and contrast controls to full.
3	Reboot the computer.
4	If the monitor stays blank, send the monitor for repair.

* Input Device Problems
Keyboards don't have technical problems, but they should be kept clean and away from dust. You shouldn't eat or drink near keyboards. Clean your keyboard periodically to avoid sticky keys. Keyboards aren't really repairable, and as the cost for keyboards and mice has lowered, the repair cost is more than the actual cost of the product.

* Storage Problems
The primary symptom of a malfunctioning storage device is that data cannot be written to or read from the device. In some cases the operating system may be unable to detect the device.
If the operating system does not detect a device, turn off the computer and check the signal and power cables to ensure that they are plugged in correctly. In the case of an external device, ensure that the device is powered on.

Sometimes USB ports don't work with USB external devices. In such a case, you should check whether USB functionality is enabled in the BIOS. If not, you should enable the functionality.

A common problem occurs when you install a new hard disk drive on an old computer and your system is not using the total capacity of the hard disk drive. The most common cause of this is that the BIOS is unable to detect a hard disk drive correctly because it does not support higher-capacity drives. A simple BIOS upgrade usually fixes this problem.

If a storage device is detected but cannot be read from or written to, check the software configuration. For hard disks, run the FDISK utility and check the partitions. Sometimes deleting and re-creating the partitions solves the problem. Sometimes the hard disk needs to be formatted for use.

* Memory Problems
Memory errors are typically accompanied by an error message such as XXXX 201 Parity check 1, where XXXX is a memory address. Sometimes the error message Incorrect memory size indicates memory problems.
As a first step, shut down the computer and ensure that the memory is correctly placed in the sockets. Removing the memory modules and reinserting them is a good practice. If the error message continues, replace the memory modules with new ones. If the problem persists, then the motherboard is probably faulty.

Memory modules typically produce the following two types of errors:

• Parity Error — When a parity error occurs, a Non-Maskable Interrupt (NMI) is generated that halts system processing and diverts the system's attention to the error. Most systems will not halt the processor when a parity error is detected. Instead they will give you the choice of rebooting or continuing as if no error has occurred. The best way to troubleshoot this problem is to remove the memory from the motherboard and test it in a SIMM/DIMM tester.
• CMOS Memory Mismatch — A computer may report a CMOS memory mismatch error at startup. This error occurs when CMOS records a memory value different from the actual memory available in the system unit. In most modern computers, the CMOS is able to update its RAM setting automatically. However, after adding memory, if you observe a CMOS memory mismatch error at startup, then you will need to invoke the CMOS setup program manually to record the new amount of memory.

Note: To determine the amount of RAM in a computer, you can check the General tab of the System Properties dialog box.


* Thermal Issues
While checking the CPU, ensure that the cooling fan mounted on top of the heatsink is operational. Blow away the dust and ensure that the fan spins freely. Check the power connection to the fan if the fan is not working. Realign the routing of the internal ribbon cables to allow maximum airflow around the CPU and memory modules.

Two types of CPU heatsinks are available:

• Passive heatsinks — Passive heatsinks are blocks of aluminum with fins. The fins sometimes get loaded with dust, reducing the cooling efficiency. Blow away the dust using compressed air.
• Active heatsinks — Active heatsinks are provided with a cooling fan to provide forced-air cooling. High quality fans use ball bearings, whereas cheaper ones use bush bearings. Bush bearings tend to wear out or seize with time. A fan with worn out or seized bearings tends to spin slowly or not spin at all. In such a scenario, the fan must be changed. The fins of an active heatsink and the fan blades get clogged with dust from time to time. Blow out the dust using compressed air.

* Adapter Card Issues
A prime indication of a problem in an adapter card is that a connected device does not function. One generic step that applies to all adapters is to ensure that the device is powered on. If the device is internal, the power cable may be loose. If the device is external, the power switch may be off.

A defective adapter card may prevent the computer from booting, without issuing a display or beep indication. This happens when the defective adapter card causes the expansion slot on the motherboard to malfunction.
In this case, pull out all of the expansion cards except for the display card, and restart the computer. If the symptoms disappear, then one of the removed cards is at fault. Proceed to plug in the cards one at a time, restarting the computer each time. In this manner, you can isolate the defective adapter.

* Identifying Troubleshooting Tools
The important concepts are:

Screwdriver

This tool can be used to open computer cases as well as to remove components installed in the computer.

Plastic tweezers

This handy tool is used for picking up tiny screws that fall on the motherboard; it's useful when working in tight places.

Flashlight

This device is used for finding dropped screws that are not visible in a dark computer case.

Multimeter

This is an electronic troubleshooting device. This tool comes in analog and digital form and measures electric pulses of voltage.

Topic 7.1 Exercises

* Exercise 1
Try identifying common display device problems on your computer system.

Step	Action
1	Take electrostatic discharge (ESD) precautions and open the system case.
2	Verify that the video adapter is properly inserted in its expansion slot.
3	Close the system case.
4	Verify that the display cable and power cable are connected properly.
5	Check the display settings.
6	Reinstall the display drivers if an image appears during the boot process but Windows cannot load.
7	If you continue to experience display problems after going through these steps, replace the video card.

In this lesson, you learned how to identify tools, diagnostic procedures, and troubleshooting techniques for personal computer components.

Lesson 8. Performing Preventive Maintenance

Computer components are sensitive and require a lot of maintenance. Technicians must be aware of the necessary maintenance techniques to avoid computer or component failure. Failures occur for a variety of reasons, ranging from human factors to environmental issues. Once a computer fails, repairing it can be expensive and time consuming. Therefore, you should keep computers away from dust and heat, and perform regular maintenance checks.
After completing this lesson, you should be able to:

• Perform preventive maintenance on personal computer components

Preventive maintenance deals with performing maintenance procedures to prevent any computer system failures. Most preventive maintenance procedures deal with keeping the computers clean and cool and performing regular software housekeeping.

* General Cleaning Techniques
The exterior surfaces of the computer, such as the system case, monitor, keyboard, and mouse, can be cleaned with a cloth dampened with a soap solution. After cleaning with the soap solution, wipe off the exterior surfaces of the computer with a damp cloth and then wipe dry. Use a lint-free cloth for all operations. Follow this with an antistatic cleaner, allowing the components to dry before use. Take care to prevent liquids from dripping into the interiors of the components.

You should avoid the use of commercial cleaning compounds, solvents, and spray cleaners. Such products can harm plastic surfaces. In particular, you should avoid using sprays on the face of the monitor.
Use only a cloth dampened with soap and water. Be careful while cleaning LCD monitors because the plastic surface scratches easily.

Electrical contacts often develop a layer of oxide that hinders the flow of current. You can remove the oxide layer and other grime by gently swabbing the surface with isopropyl alcohol using a cotton swab.
Most adapter boards and sockets use gold-plated contacts. You should unplug and then plug them back in to improve the connection.

* Ventilation
The components inside the system case tend to heat up during normal use. Under normal circumstances, the power supply unit fan cools the components by forcing air through the case. If temperatures rise enough, the cooling provided by the fan may be inadequate.
Temperatures also tend to rise if the air that is expelled through the vents in the system case is obstructed. High temperatures may cause intermittent errors and may lead to component failure. High humidity may lead to corrosion of electrical contacts, which leads to computer malfunction.

To minimize problems due to heat buildup and humidity, ensure that:

• Books and stationary items scattered around the computer do not obstruct the airflow from the system case.
• Heaters in the room do not heat the computer. Keep computers away from heaters. Do not place computers where direct sunlight falls on them. Sunlight may lead to overheating.

Note: Computer furniture is designed to allow the free flow of air from within the system case.


* Driver/Firmware Updates
Firmware is a set of programs and data always available to the computer's processor. Programs and data are stored as firmware under the following circumstances:

• Secondary storage is inaccessible when the program or data are required. An instance of this occurs at boot time, when the BIOS routines including the firmware are required before the secondary storage devices become active.
• Access must be faster than secondary storage can provide. An example of this is the video BIOS firmware provided in some graphics cards.

You should update firmware periodically to avoid BIOS issues. For example, you should update the BIOS firmware when it does not support new hardware.

* Electrostatic Discharge (ESD)
ESD is a hazard for computer components. Static charges are electric charges that build up on most insulating material. The flow of static current is termed electrostatic discharge. Although the voltages involved are high, static charges are harmless to humans because the currents involved are small. However, ESD is harmful for electronic components and can permanently damage circuits.

* Anti-Static Wrist Strap
An anti-static wrist strap is an ESD device that grounds your body and keeps it at zero charge, preventing static electricity discharges. You must use an ESD strap to avoid damage to components. To use an ESD strap, attach one end to a grounded source and wrap the other end around your wrist.

* Compressed Air and Vacuum Cleaners
Keep internal components dust free. You should clean all the components regularly to prevent dust from accumulating inside the computer. Compressed air cans are used for cleaning computer components and as a blower to remove dust from the computer. You should power off the computer before removing dust from inside it.

To remove dust internally, remove the covers from the system case and vacuum loose dust from the inside. Use compressed air to blow off the remaining dust.
Using a vacuum cleaner helps to avoid redistributing dust. You can also clean the keyboard, mouse, and removable media drives in a similar manner.

Topic 8.1 Exercises

* Exercise 1
Try cleaning the outside and internal components of your system.

Step	Action
1	Clean the exterior surfaces of your computer.
2	Power off the computer system.
3	Take electrostatic discharge (ESD) precautions and remove the covers from the system case.
4	Remove any loose dust from inside.
5	Replace the covers and seal the system case.

In this lesson, you learned how to perform general cleaning techniques, ensure proper ventilation, and do other types of preventive maintenance to avoid computer or component failure.

Lesson 9. Course in Review

This lesson lets you review the CompTIA A+ Essentials principles and practices. It reviews the course material through questions and an exercise.

Topic 9.1 Exercises

* Exercise 1
Try installing a new video adapter card into your computer.
Please Note: For the exercises in this course, you should set up a standalone system for practice. Do not use your production system for these practice exercises.

Step	Action
1	Power off the computer and disconnect all cables from the system case.
2	Take electrostatic discharge (ESD) precautions and open the system case.
3	Locate an unused expansion slot compatible with the adapter card that you are installing or remove your old video card.
4	If required, set the configuration jumpers on the new card.
5	Insert the new video adapter card into the slot.
6	Secure the video adapter card.
7	Seal the system case.
8	Reattach all external cables.
9	Restart the computer. Note: You may need to run a vendor-supplied utility to install drivers.