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1.2 Given a scenario, detect problems, troubleshoot and repair/replace personal computer components
- Storage devices
- HDD
Troubleshooting Hard Disk Drives
- SATA
- Standard defines a seven conductor data cable with a 15 pin power connector
- Suplied voltages include 3.3 V, 5 V, and 12 V
- PATA
Parallel ATA, sometimes refered to as Ultra ATA or IDE, transfers data in parallel at the rate of 133MB per second. Up to two drives can be connected to the motherboard per controller port (4 max), through the use of either a 40 or 80 wire cable connected to a 40-pin connector on the back of the drive.
- Solid state
- Uses memory to store data
- Contains no moving parts, quieter
- Resistant to shock and vibration
- Faster read/write speeds
- Lower power consumption
- FDD
Though rapidly becoming obsolete, floppy disk drives may be found in some legacy systems and are often still used for archival applications. The most recent configuration accepted a removable 3 1/2" disk with a storage capacity of 1.44 MB and were traditionally assigned drive letters A and B.
Typically, a floppy disk drive is installed into a 3 1/2" drive bay. Data is transferred to and from the motherboard through a keyed 34-pin flat ribbon cable and power to the drive is provided by a 4-pin polarized Berg connector.
- Optical drives
There are three primary types of optical storage media in use today. Compact Discs (CD), Digital Versatile Discs (DVD), and Blu-Ray discs. Data is recorded to this type of media by stamping irregularities onto the surface of the disc, or "burned" into it using a laser, in a spiral pattern that runs from the inside to the outside of the disk. The data is read back from the disc using a laser. Differences in reflection caused by the variations in the plastic layer are detected and translated as 0s and 1s.
Most internal drives are designed to fit in a standard 5.25" drive bay. Internal connections may be provided by either a PATA or SATA interface and may require additional outputs to the sound card or the motherboard for audio.
- CD
Used for digital data storage, Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to 80 minutes of uncompressed audio or 700 MB (700 × 220 bytes) of data. Formats include read-only (CD-ROM), write-once audio and data storage (CD-R), and rewritable media (CD-RW).
- DVD
- 4.7GB capacity(single-sided/single-layer)
- 8.5GB capacity (single-sided/double-layer)
- 9.4GB capacity (double-sided/single-layer)
- 17.1GB capacity (double-sided/double-layer)
- RW
CD-R and CD-R/RW recorders employ several different writing modes. Not all recorders and software support every writing mode.
- Blu-Ray
- High-density optical disc
- 25-50GB storage capacity single-layer
- 50-100GB storage capacity dual-layer
- Removable
Removable Storage allows for the transfer and transportation of data. Removable storage may include floppy or hard disks, rewritable optical media, or portable USB drives. The amount of storage space available on removable storage has drastically increased over the years, and continues to increase as new technology is developed.
- External
Provides portable storage with popular interfaces of USB and FireWire. Some are available with an eSATA or SCSI interface and some still require additional power sources.
- Motherboards
The motherboard is the main integrated circuit board (ICB) within a computer. Also referred to as the main board or mobo for short, it is the primary interface for all of the other components in a computer. All of the other components must comply to certain specifications and guidelines in order to function properly with each specific motherboard.
- Jumper settings
Jumper settings, once used extensively in computers, are a mechanical means of setting configuration options.
- CMOS battery
The memory and real-time clock are generally powered by a 3 volt CR-2032 lithium coin cell battery. These cells typlcally last two to ten years before needing replacement. When replacing the cell, the system time and CMOS BIOS settings may revert to default values.
- Advanced BIOS settings
The BIOS (Basic Input/Output System) is a special software that handles the basic interface between the operating system and the major hardware components of your computer. The BIOS contains the necessary code required to control the keyboard, display screen, disk drives, serial communications, and a number of other functions.
On start-up, the BIOS performs several tasks. It will first read the CMOS Setup for any configuration instructions specific to the unit. It will also load device drivers, perform the power-on self-test (POST), and initiate the boot sequence.
Configuration settings for the BIOS are usually stored on a Flash memory chip on the motherboard, often called a ROM BIOS, and retains this information when the unit is powered down. This ensures that the BIOS will always be available and not damaged by disk failures. The BIOS can be accessed directly at startup by pressing DEL or a function key (usually F2). Inexperienced users should not make changes to the BIOS settings.
- Bus speeds
A computer bus is an electrical pathway through which the processor communicates with the internal and external devices attached to the computer. It connects all internal computer components to the main memory and the CPU. Some motherboards have multiple busses used for different functions.
Each bus is defined by it's width (the number of bits of data that can be transferred at once), it's speed measured in cycles per second or megahertz (MHz), and refers to the amount of data that can move across the bus simultaneously.
Width x speed = throughput
- More Information -
- Chipsets
The chipset typically refers to a group of integrated circuits designed to provide a means of communication between the CPU and other components and peripherals found throughout the computer.
- Firmware updates
The term firmware references the control programming code necessary for certain devices to function, typically stored in a non-volatile memory device such as ROM, EPROM, or flash memory. Most firmware applications will last throughout the usefull life of the device. However, there are occasions which will require the firmware to be updated, whether it is necessary to keep up with emerging technologies, patch vulnerabilities in the code, or to repair a corrupt firmware application.
Firmware updates are typically made available at the manufacturer's website. These can be downloaded as a binary file and often applied with the help of an installation application.
Warning:
Once a firmware update has been initiated, the process must NOT be interrupted.
- Socket types
- The interface that connects the processor to the motherboard.
- Mounted permanantly on motherboard
- Designed to accomodate specific processor packages
- Expansion slots
An expansion slot is an electrical connector on a computer motherboard or riser card that is designed to add functionality or increase the functionality of a computer system via the expansion bus.
Common examples of expansion slots include ISA (Industry Standard Architecture), AGP (Accelerated Graphics Port), PCI (Peripheral Components Interconnect), and PCI Express. Laptop or notebook computers are generally designed to accept the CardBus, PC card, or PCMCIA technologies which were later replaced by the ExpressCard versions.
- Memory slots
Memory slots are electrical connectors on a computer motherboard designed to hold the integrated circuit board that houses the system memory. There are typically 2 - 4 slots available, designed to accept the particular type of RAM designed for use with each board.
Common examples of memory slots include SIMM (Single Inline Memory Module), DIMM (Dual Inline Memory Module), and RIMM (Rambus Inline Memory Module).
- Front panel connectors
Most PCs come equipped with a built-in front panel. At a minimum, these panels will contain at least two switches, On/Off and Reset, and two LEDs, one displays power status while the other indicates hard drive activity. Some Front Panels may come equipped with audio ports, while others may contain Firewire or USB ports. Each switch and LED on the front panel has a connector attached to it that must be connected to the appropriate pins on the motherboard. Some must be connected in the correct polarity (+ or -). Front Panel connections do not follow an accepted standard and therefore may be labeled in a variety of ways. A power switch might be labeled as PWR-SW, PW SW, or PW. Likewise, the internal speaker may be indicated by SPK, SPKR, or SPEAK. Alwaws consult the Motherboard Owner's Manual for specific instructions.
Front Panel I/O Connectivity
Design Guide
- I/O ports
I/O interface or ports refers to the physical connection between the computer and any attached device or communication circuit. These interfaces are generally located on the back of the computer or the front panel. These connections generally provide an electrical circuit for power, and the means of transferring data. A different interface is required for each type of I/O device or connection and must follow specific standards for that connection.
- Sound
Mini-audio jack, 1/8" jack, 3.5mm jack.
- Video
- VGA - Video Graphics Array DC-15 connector
- DVI - Digital Video Interface
- S Video
- HDMI - High Definition Multimedia Interface
- USB 1.1, USB 2.0
Universal Serial Bus, hot-swappable, powered through the USB connection, USB A, USB B and USB mini-B connections.
- Serial
- Typical serial ports include 9-pin and 25-pin connection
- Compliant to the RS-232 standard
- Information is transfered in or out in a single-bit stream
- Newer technology includes Ethernet, FireWire, and USB
- IEEE 1394 / Firewire
- 1394a - 400MB/s
- 1394b - 800MB/s
- Parallel
Also known as a printer or Centronics port, a 25-pin computer interface designed for bi-directional communication. Defined under the IEEE 1284 standard.
- NIC
- Network Interface Controller
- Provides communication between the computer and the network
- Modern onboard interface is typically an RJ-45 connection
- Modem
Acronym for modulator-demodulator. Provides analog phone line communication between the computer and a telephone network. Interface is provided through an RJ-11 connection with 56Kb/s maximum transmission speed.
- PS/2)
Also refered to as a mini-DIN connection, this smaller version of the DIN connection is commonly used to connect the keyboard or mouse.
- Power supplies
A computer's power supply converts the AC (alternating current) provided by the main electrical supply of your home or office to DC (direct current) needed to operate the device. Power supplies may vary greatly in appearance and technical specifics (input and output) from one device to another.
A components form factor defines it's physical diminsions and characteristics. As a general rule, the form factor of a computer's components, the case, power supply, and motherboard, must all match.
- Wattages and capacity
Wattage measures the rate of energy conversion and is figured by multiplying volts times amps (volts x amps = watts).
Ampherage is the rate of the electron flow. The more electrons that flow past a given point at a given time, the higher the ampherage.
- Connector types and quantity
Power Supply Connectors
- Output voltage
Voltage is the measure of electrical potential difference between two points. Voltage can be measured between two points with a voltmeter. Computer power supplies traditionally accept alternating current (AC) as input and produce direct current (DC) as output.
- Processors
The CompTIA A+ exam will focus primarily on processors developed by AMD and Intel. CPUs must be compatible with the motherboard.
- Socket types
- The interface that connects the processor to the motherboard.
- Mounted permanantly on motherboard
- Designed to accomodate specific processor packages
- Speed
Clock speed is rated in cycles per second and measured in hertz (Hz), 3.2 billion cycles per second = 3.2 gigahertz (GHz).
- Number of cores
- Power consumption
- Cache
Because processors can read data so much faster than main memory, a better method of accessing data was needed to provide an adequate level of efficiency. This was accomplished by storing pieces of recently accessed information within the processor cache. Processor cache is a very small amount of very high speed memory usually embedded in the die of the processor. Typically, there are two levels of cache used, Level 1 and Level 2.
Level 1 cache feeds the CPU and provides the fastest access to the data used most often.
Level 2 cache feeds the L1 cache. L2 cache is slower than L1, but it is usually larger in size.
- Front side bus
- Memory Controller Hub
- Controls communication between the CPU, Ram, and video controller
- 32bit vs. 64bit
32-bit and 64-bit Explained
Microsoft Frequently Asked Questions
- Memory
Memory types have changed through the years, driven by standardization and technology. It is one of the most important components of your computer, but differs somewhat with each motherboard.
- Adapter cards
Expansion cards are printed circuit boards that can be inserted into an expansion slot of a computer motherboard, and are designed to add versatility and expand the functionality of a computer. Depending on the form factor of the motherboard and case, one to seven expansion cards can be added to a computer system. Over time, changes in technology have required design changes to accomodate. Each card must meet the same exacting standards as the expansion slot it will be installed into.
- Graphics cards - memory
The AGP (Accelerated Graphics Port) is a high-speed point-to-point channel for attaching a single graphics card to a computers motherboard, primarily to assist in the acceleration of 3D computer graphics. AGP provides a direct connection between the video adapter and the CPU but has been replaced by PCI-Express technology.
AGP versions include:
- AGP 1.0 - 3.3 volts signaling with speed multipliers 1x (267MB/s), 2x (533MB/s)
- AGP 2.0 - 1.5 volts signaling with speed multipliers 1x (267MB/s), 2x (533MB/s), 4x (1067MB/s)
- AGP 3.0 - 0.8 volts signaling with speed multipliers 4x (1067MB/s), 8x (2133MB/s)
- Sound cards
A sound card is an internal computer expansion card providing an audio input and output interface with connections for speakers, headphones, and microphone.
- Storage controllers
- I/O cards
- Firewire
- USB
Provides additional USB connections.
- Parallel
Provides additional parallel connections.
- Serial
Provides additional serial connections.
- Wired and wireless network cards
- Capture cards (TV, video)
Used to capture analog and S-Video formats. Some cards support digital video and HDMI in both standard definition (SD) and high definition (HD). Analog signals can be converted into digital media, recorded, used for video surveillance, or live streaming video.
- Media reader
- Cooling systems
- Heat sinks
Typically made from aluminum or copper, heat sinks are designed to transfer heat away from components through conduction.
- Thermal compound
Designed to fill imperfections or gaps between the component and heat sink to promote heat transfer. Pre-existing compound should be cleaned and reapplied any time the heat sink is removed.
- CPU fans
Provides air cooling, the most common method of cooling.
- Case fans
Provides air cooling, the most common method of cooling.
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