A Guide to Managing and Maintaining your PC, 6e - PowerPoint PPT Presentation

1 / 48
About This Presentation
Title:

A Guide to Managing and Maintaining your PC, 6e

Description:

Wires on the case match connections on motherboard ... Designed for low-end PC motherboards. NLX form factor. Developed to improve the LPX form factor ... – PowerPoint PPT presentation

Number of Views:128
Avg rating:3.0/5.0
Slides: 49
Provided by: conest
Category:

less

Transcript and Presenter's Notes

Title: A Guide to Managing and Maintaining your PC, 6e


1
A Guide to Managing and Maintaining your PC, 6e
  • Chapter 4
  • Form Factors and Power Supplies

2
Objectives
  • Learn about different form factors and computer
    cases
  • Learn how electricity is measured
  • Learn how to protect your computer system against
    damaging changes in electrical power
  • Learn about Energy Star specifications
  • Learn how to troubleshoot electrical problems

3
Introduction
  • Power supply passes power to PC components
  • Elements driving type of power supply used in a
    PC
  • The motherboard
  • The form factor of the computer case
  • Energy Star devices designed to save energy
  • Electricity topics covered
  • Measurements of electricity
  • How electricity is delivered
  • Protecting a PC from electrical damage
  • Changing a defective power supply

4
Computer Case, Motherboard, and Power Supply Form
Factors
  • Form factor
  • Specifies size, shape, features of a hardware
    device
  • Form factor for motherboard is chosen first
  • Same form factor is used for case and power
    supply
  • Using the same form factor assures you that
  • The motherboard fits the case
  • The powers supply cords provide proper voltage
  • Holes in the motherboard align with holes in the
    case
  • Holes in the case align with ports off the
    motherboard
  • Wires on the case match connections on motherboard

5
Types of Form Factors
  • AT (Advanced Technology) form factor
  • Specified motherboard dimensions of 12 x 13.8
  • Utilized by IBM AT PC in the 1980s
  • Baby AT form factor
  • Specified motherboard dimensions of 13 x 8.7
  • Industry standard form factor from 1993 to 1997
  • ATX form factor
  • Specified motherboard dimensions of 12 x 9.6
  • Open specification that is most commonly used
    today
  • Includes all AT voltages plus a 3.3-volt circuit

6
Figure 4-4 The CPU on an ATX motherboard sits
opposite the expansion slots and does not block
the room needed for long expansion cards
7
Types of Form Factors (continued)
  • MicroATX form factor
  • Reduces number of I/O slots on the motherboard
  • BTX (Balanced Technology Extended) form factor
  • Focuses on reducing heat and supporting
    motherboard
  • LPX and Mini-LPX form factors
  • Designed for low-end PC motherboards
  • NLX form factor
  • Developed to improve the LPX form factor
  • Backplane Systems (Active and Passive)
  • Use boards with slots, but little or no circuitry

8
Figure 4-8 Improved airflow in a BTX case and
motherboard makes it unnecessary to have a fan on
top of the processor
9
Types of Cases
  • Computer case (chassis)
  • Houses power supply, motherboard, cards, drives
  • Panel switches/lights are used to control/monitor
    PC
  • Desktop cases
  • Motherboard on the bottom, power supply to the
    rear
  • Tower cases
  • Are up to 2 feet high and can contain several
    drives
  • Notebook cases
  • Used for all portables and have desktop
    components

10
Figure 4-13 Tower and desktop cases
11
Measures and Properties of Electricity
  • Successful PC technicians
  • Understand electricity
  • Know how to use electricity
  • Know how to measure electricity
  • Can protect computer equipment from electricity
  • Units used to measure characteristics of
    electricity
  • Volt, amp, ohm, and watt

12
Table 4-2 Measures of electricity
13
AC and DC
  • Alternating current (AC)
  • Oscillatory current driven by an alternating
    voltage
  • Example house current oscillates at 60 Hz
  • Direct current (DC)
  • Single direction current driven by constant
    voltage
  • Required by computer in small amounts, such as 5
    V
  • Rectifier converts AC to DC
  • Transformer changes ratio of current to voltage
  • Power supply acts as a transformer and rectifier

14
Figure 4-15 A transformer keeps power constant
but changes the ratio of current to voltage
15
Hot, Neutral, and Ground
  • Completing a circuit
  • AC travels from power station to house on a hot
    line
  • AC travels from panel to device using black (hot)
    wire
  • AC flows out of device circuit in a white
    (neutral) wire
  • AC returns to power station on a neutral line
  • Short circuit failure due to excess flow of
    electricity
  • Fuses protect circuits by melting wire (breaking
    circuit)
  • Grounded neutral lines pass detoured AC to earth
  • Lines in three-prong plugs hot, neutral, and
    ground
  • Verify wiring of outlet for plug using a
    receptacle tester

16
Figure 4-16 Normally, electricity flows from hot
to neutral to make a closed circuit in the
controlled environment of an electrical device
such as a lamp
17
Figure 4-18 Use a receptacle tester to verify
that hot, neutral, and ground are wired correctly
18
Some Common Electric Components
  • Materials used to make components
  • Conductors weakly resist flow of current e.g.,
    copper
  • Insulators highly resist flow of current e.g.,
    ceramics
  • Semiconductors allow flow if charged e.g.,
    silicon
  • Transistor
  • Used to switch current on (1) and off (0)
  • Also used to amplify current
  • Made of three layers of semiconductor material
  • Charge applied to center layer controls switching

19
Figure 4-19 Symbols for some electronic
components and for ground
20
Some Common Electric Components (continued)
  • Capacitor
  • Holds electrical charge for a period of time
  • Used to create even flow of current in a PC
  • Diode
  • Allows electricity to flow in one direction only
  • Used to rectify current (convert AC to DC)
  • Resistor
  • Controls the amount of current flowing through
    device
  • Degree of resistance is measured in ohms

21
Figure 4-20 Capacitors on a motherboard or other
circuit board often have embedded crossed lines
on top
22
Protecting Your Computer System
  • Electrical threats to a computer system
  • Static electricity
  • Electromagnetic interference
  • Power surges
  • Objectives in this section
  • Understand nature of each threat
  • Learn how to protect your system from these
    threats

23
Static Electricity
  • Static electricity (electrostatic discharge or
    ESD)
  • Due to charge difference between user and device
  • Touching device causes discharge, damaging device
  • ESD is particularly severe in dry and cold
    climates
  • How to protect system from ESD
  • Use ground bracelet or ESD gloves
  • Touch computer case before touching components
  • Safety rule unplug power cord before working in
    case
  • Residual power in plugged device can cause damage

24
EMI (Electromagnetic Interference)
  • Caused by magnetic fields generated by current
    flow
  • RFI (radio frequency interference)
  • EMI in radio frequency range affecting reception
  • The crosstalk problem
  • Data in cables crossing EM fields gets corrupted
  • Control crosstalk by shielding cables and power
    supply
  • Use a tuned-down AM radio to detect EMI
  • Other ways to protect a device from EMI
  • Use line conditioners to filter out electrical
    noise
  • Move the PC to a new location

25
Surge Protection and Battery Backup
  • Storms and uneven AC flow cause power surges
  • Prevent power surges by installing an AC filter
  • Types of devices used to manage power surges
  • Surge suppressors
  • Power conditioners
  • Uninterruptible power supplies (UPSs)
  • Use devices with UL (Underwriters Laboratory)
    logo

26
Surge Suppressors
  • Also called a surge protector
  • Protects equipment from sudden changes in power
  • Works by absorbing and/or blocking the surge
  • Recommended features
  • Joules rating that is greater than 600 joules
  • Protection activated in less than 2 nanoseconds
  • Warranty for connected equipment and UL seal
  • Light indicating that surge protection is working
  • Data line protector for telephone line to modem
  • Let-through voltage rating and line noise
    filtering

27
Figure 4-21 This surge suppressor has six
electrical outlets, two phone jacks, and a power
protection light
28
Power Conditioners
  • Sometimes called line conditioners
  • Functions
  • Protect against spikes or swells (voltage surges)
  • Raise voltage during brownouts (voltage sags)
  • Load supported measured in watts or volt-amps
    (VA)
  • Determining the VA needed to support your system
  • Multiply the amperage of each component by 120 V
  • Add up the VA for each component

29
Uninterruptible Power Supply
  • UPS offers three benefits
  • Conditions line to account for brownouts and
    spikes
  • Provides power backup when AC fails (blackout)
  • Provides protection against very high spikes
  • Designs standby, inline, and line-interactive
  • Smart (intelligent) UPS controlled with software
  • What to consider when buying a UPS
  • UPS rating should exceed VA load by at least 25
  • Degree of line conditioning
  • Warranties, guarantees, and service policies

30
Energy Star Systems (The Green Star)
  • Energy Star systems have the U.S. Green Star
  • Indicates device meets energy conserving
    standards
  • Devices computers, monitors, printers, copiers,
    faxes
  • Goals of Energy Star (a.k.a. Green) standards
  • Reduce overall electricity consumption
  • Protect and preserve natural resources
  • How computer components meet standards
  • Uses standby program for switching to sleep mode
  • No more than 30 watts used during sleep mode

31
Power-Management Methods and Features
  • Methods used to meet Energy Star standards
  • Advanced Configuration and Power Interface (ACPI)
  • Standard used by most desktops and notebooks
  • Comprises four power-saving modes S1 - S4
  • Some features controlled by BIOS, others by
    Windows
  • Advanced Power Management (APM) specification
  • AT Attachment (ATA) for various drives
  • Display Power Management Signaling (DPMS)

32
Figure 4-24 A power management BIOS setup screen
showing power-management features
33
Energy Star Monitors
  • Display Power Management Signaling (DPMS)
  • Specifications applying to video card and monitor
  • Allow both devices to simultaneously enter sleep
    mode
  • Accessing energy settings in Windows 2000/XP
  • Right-click the desktop and select Properties
  • The Display Properties dialog box opens
  • Click the Screen Saver tab
  • If monitor is Energy Starcompliant, logo is at
    bottom
  • Click Power button to open Power Options
    Properties

34
Figure 4-25 Changing power options in Windows XP
35
Troubleshooting the Electrical System
  • Problems can occur before or after boot
  • Problems can be consistent or inconsistent
  • Possible symptoms of an electrical problem
  • The PC appears dead
  • The PC sometimes halts during booting
  • Error codes or beeps occur during booting
  • You smell burnt parts or odors
  • Check the simple things first
  • Example determine whether all switches are on

36
Problems with External Power
  • Brownout (reduced current) may create issues
  • Check out other devices using the same circuit
  • Remove other devices to see if voltage increases
  • Dealing with intermittent errors caused by noise
  • Use a line monitor to monitor and condition
    voltage

37
Problems with Loose Internal Connections
  • Can cause a system to appear dead or reboot
    itself
  • Troubleshooting tasks
  • Remove the cover of the case
  • Check all power connections
  • Check cables linking power supply to motherboard
  • Check cables linking power supply to drives

38
Figure 4-26 For an ATX or BTX power supply, the
remote switch wire must be connected to the
motherboard before power will come on
39
Problems that Come and Go
  • Intermittent symptoms indicating a post-boot
    problem
  • The computer stops or hangs or reboots for no
    reason
  • Memory errors appear intermittently
  • Data is written incorrectly to the hard drive
  • The keyboard stops working at odd times
  • The motherboard fails or is damaged
  • Power supply overheats and becomes hot to the
    touch
  • The power supply fan becomes very noisy or stops
  • Intermittent problems are often difficult to
    solve

40
Problems with an Inadequate Power Supply
  • Power supply may not meet needs of new devices
  • Testing for an adequate power supply
  • Make all devices in the system work at the same
    time
  • Example copy files from new drive to old drive
  • Simple solution upgrade to a higher power supply
  • Calculating total wattage needed by system
  • Multiply volts in circuit by amps required for
    device
  • Add all products to determine total wattage
  • Power supply range 200 watts to 600 watts

41
Problems with the Power Supply, Boards, or Drives
  • Issues
  • Inadequate or faulty power supply
  • Components drawing power might be bad
  • Problems caused
  • System hangs or gives intermittent errors
  • System reboots or does not boot at all
  • Actions to take
  • Isolate and remove any faulty expansion cards
  • Upgrade or switch the power supply
  • Test voltage output of power supply with a
    multimeter

42
Problems with the Power Supply Fan
  • Defective fans usually hum before they stop
    working
  • Response to diagnosis of defective fan
  • Replace fan or the entire power supply
  • If replacement does not work, suspect another
    short
  • Do not operate a PC if the fan does not work
  • Computers will overheat, damaging circuit boards
  • Indirect sources of fan problems
  • Shorts in drives, motherboard, or expansion cards

43
Power Problems with the Motherboard
  • Bad contact between board component and chassis
  • Short can seriously damage the motherboard
  • Check for missing or extra standoffs (spacers)
  • Shorts in the circuit on the motherboard
  • Look for damage to the bottom of the motherboard
  • Look for burned-out capacitors
  • Frayed wires on connections can also cause shorts
  • Test hard drive cables connected to motherboard

44
Problems with Overheating
  • Causes intermittent problems
  • May also cause the system to reboot or not boot
  • Temperature in a case should not exceed 100 F
  • Some possible solutions
  • Remove dust from power supply, vents, heat sink
  • Secure cables and cords with tie wraps
  • Install another exhaust fan on the rear of the
    case
  • Install a fan in expansion slot next to video
    card
  • Replace component that is damaged

45
Figure 4-27 Install one exhaust fan on the rear
of the case to help pull air through the case
46
Replacing the Power Supply
  • The power supply is a field replaceable unit
    (FRU)
  • Criteria for replacement power supply to meet
  • Uses the correct form factor
  • Adequately rated for power in watts
  • Has all power connectors needed by your system
  • Before replacing power supply, test new device
  • Connect components to new power supply
  • Turn on PC and observe whether problem is solved
  • If problem is solved, perform replacement
    procedure

47
Summary
  • Form factor specifies size, shape, features of
    device
  • Motherboard, power supply, and case share the
    same form factor, such as ATX
  • Three types of cases desktop, tower, and
    notebook
  • Quantities that characterize electricity
    voltage, current, resistance, and power
  • Current flows from hot wires to neutral wires
    excess current escapes through grounds

48
Summary (continued)
  • AC supplied by power station is transformed and
    rectified before flowing into the PC
  • Major components in a circuit board transistor,
    capacitor, diode, resistor
  • Electrical threats ESD, EMI, uneven current
    flow, sudden power surges (or spikes)
  • Energy Star standards promote energy conservation
  • PCs comply with Energy Star standards by enabling
    devices to enter into a low power sleep mode
Write a Comment
User Comments (0)
About PowerShow.com