Computer Maintenance
CompTIA A+ Guide to Managing & Maintaining Your PC
By: JEAN ANDREW
Chapter 3:
Power supplies and Form Factors
Objectives
After you have completed this lesson,
you will be able to:
• Identify different kinds of power supply, computer
case, and form factor
• Describe how electricity is measure
• Protect your computer system against damaging
changes in electrical power
• Describe Energy Star specifications
• Install power supply & troubleshoot electrical
problem
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Computer Case, Motherboard and
Power Supply
• Form Factor describes the size, shape, and major
features of a hardware component.
• The Form Factor of motherboard, power supply,
and case must all match
• Using a matching form factor for the mother
board, power supply, and case assures you that:
–
–
–
–
The motherboard fit in the case
The power supply cords and voltage match to the board
The holes in motherboard align with the hole in the case
Holes in the case align with port coming of the
motherboard
– For some form factors, wires for switches and lights on
the front of the case match up with connection on the
board
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Computer Case, Motherboard and
Power Supply
A computer case is also known as a chassis
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Type of Form Factor
• Different form factors apply to power supplies,
cases, and motherboards:
–
–
–
–
–
–
BTX
ATX
LPX
NLX
Backplane systems
AT form factor (outdated)
• The most common form factor: ATX, MicroATX,
BTX, and NLX
• The most popular form factor is ATX
• BTX is the latest
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Type of Form Factor
12” x 13.8 “
1980s
+5, -5, +12, -12 volts
Uses p8, p9 connector
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Type of Form Factor
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Type of Form Factor
12” x 9.6”
most common
by Intel 1995
better arrange
reduce EMI
installing simpler
CPU beside
expansion slot
blow air out of
case
use P1 connector
Soft switch or
soft power
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Type of Form Factor
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Type of Form Factor
• MicroATX Form Factor
– Reduce total cost of a system by reducing:
I/O slots on the motherboard
 Power supply to the motherboard
 Allowing for a smaller case size

• BTX (Balanced Technology Extended) Form Factor
–
–
–
–
Flexible and can be use by large to small system
Support ATA, USB 2.0, and PCI Express technologies
Reducing heat with better air flow, improve fan and cooler
Use 24-pin power connector
• LPX and Mini-LPX Form Factors
– Develop by Western Digital
– Use small case call low-Profile cases and slimline cases
– Has only one expansion slot with a riser card mounted
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Type of Form Factor
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Type of Form Factor
• NLX Form Factor
–
–
–
–
For low-end personal computer motherboard
Developed by Intel in 1998 to improve old LPX
The riser card is on the edge of the board
Designed to use ATX power supplies
• Backplane Systems
– Do not use a true motherboard
– Active Backplane: no circuit other than connectors and
some buffer and driver circuits
– Passive backplanes: contain no circuitry at all
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Type of Form Factor
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Type of Form Factor
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Type of Cases
• Desktop Cases
– Classic case with four drives bay and around six
expansion slots
– A monitor is stand on the case
– The motherboard sits on the bottom of the case with
power supply at the back
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Type of Cases
• Tower Cases
–
–
–
–
Can be as high as two feet and has several room drives
Often used for servers, and good for PC users for upgrade
Provide maximum space for working inside
The variations in case are as follows:
Midsize towers, also called miditowers are the most popular
 Have around 6 expansion slots and 4 hard drives bays
 Used for ATX, Mini-ATX, and BTX systems

• Minitower (Microtower)
– Is the smallest type of tower case, no room for expansion
• Full-size towers
– Used for high-end personal computers and servers
– Build for ATX, Mini-ATX, and BTX system
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Type of Cases
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Type of Cases
• Notebook case
– Are used for portable computers
– Conserve space, allow portability, use less power,
produce less heat
Manufacturer
Web site
Asus
www.asus.com
Axxion Group Coperation
www.axxion.com
Enlight Corporation
www.enlightcorp.com
Maxpoint Computers
www.enermaxusa.com
MGE Company
www.mgecompany.com
PC Power and Cooling
www.pcpowerandcooling.com
PCI Case Group
www.pcicase.co.uk
Sunus Suntek
www.suntekgroug.com
Table 4-1 Manufacturers of cases and power supplies for personal computers
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Measures and Properties of
Eelectricity
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Power supplies and Form Factors
AC and DC
• AC (alternating current): goes back and forth
• DC (direct current): travel in only one direction
– Rectifier: is a device that converts AC to DC
– Transformer: is a device that changes the ratio of current
to voltage
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Some Common Electronic
Components
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Protecting Your Computer System
• Static Electricity (or ESD)
– Is the phenomenon that can damage component when
you touch these components. To protect ESD use:

Ground bracelet or static strap

Ground mats

Static shielding bags
• EMI (Electromagnetic Interference)
– Is cause by magnetic field produced as a side effect when
electricity flows
• Surge Protection and Battery Backup (UPS)
– Surge Suppressors (surge protector)
– Power Conditioner
– Uninterruptible Power Supply
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Protecting Your Computer System
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Protecting Your Computer System
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Protecting Your Computer System
• What to consider when buying a UPS
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Energy Star Systems (The Green
Star)
• Also called Green Standards:
– A computer or devices that conforms to these standards
can go into sleep or doze mode when not in use, thus
saving energy and helping the environment.
• Power-management method and features
–
–
–
–
ACPI (Advance Configuration and Power Interface)
APM (Advanced Power Management)
AT Attachment (ATA)
Display Power Management Signaling (DPMS)
• Energy Star Monitor
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Energy Star Systems (The Green
Star)
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Scenario
In this chapter, you will learn:
– Computer case, Motherboard, and Power Supply
Form Factor
– Type of Form Factor
– Types of cases
– Measures and properties of electricity
– Protect your computer system
– Energy Star system
– Troubleshooting the electrical system
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Troubleshooting the Electrical
System
• Possible symptoms of a problem with the electrical
system are:
– The PC appears “dead”—no lights, no spinning drive or fan
– The PC sometimes halts during boots. After several tries, it
boots successfully.
– Error codes or beeps occur during booting, but they come
and go.
– You smell burnt parts or odors. (Definitely not a good
sign!)
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Troubleshooting the Electrical
System
• Check the simple things firs. Try these things:
– Is everything connected and turned on? Are any
cable connections loose? Is the computer
plugged in?
– Are all the switches turn on?
– If the fan is not running, turn off the computer,
open the case (Check connection of cable, are all
card securely seat)
– If you smell burnt parts, turn off the system and
carefully search for the source of the problem
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Troubleshooting the Electrical
System
• Problems with external power
• Problem with loose internal connections
• Problem that come and go
• Problem with an inadequate power supply
• Problem with the power supply, boards, or drives
• Problem with the power supply fan
• Problem with the mother board
• Problem with overheating
• Replacing the power supply
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Summary
active backplane
electromagnetic
interference (EMI)
passive backplane
alternating current (AC)
Energy Star
Power conditioners
AT
field replaceable unit
(FRU)
rectifier
ATX
Flex ATX
resistor
Baby AT
Form factor
sags
backplane system
full AT
sleep mode
BTX (Balance Technology
Extended)
Green Standard
slimline case
bus riser
intelligent UPS
smart UPS
capacitor
LPX
surge suppressor
diode
Micro-ATX
tower case
direct current (DC)
Mini-LPX
transformer
desktop case
NLX
transistor
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Summary
• Form Factor is a set of specifications for the size
and configuration of hardware components, such
as case power supplies and mother boards.
• The most common form factor is ATX. The other
like AT, Baby AT, BTX, LPX and NLX, Backplane
System.
• Case type include desktop, low-profile or slimline
desktop, minitower, miditower, full-size tower and
notebook. Miditower is the most popular today.
• Microcomputer requires Direct Current, which
convert from AC (Alternating Current).
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Summary
• A power supply is actually a transformer and
rectifier, rather than a supplier of power.
• A transistor is a gate or switch for an electrical
signal, a capacitor holds an electrical charge, a
diode allow electricity to flow in one direction, and
a resistor limits electrical current.
• To protect a computer against ESD, use a ground
bracelet, ground mat, and static shielding bags.
• Device that control the electricity to a computer
include surge suppressors, line conditioner, and
UPS.
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Power supplies and Form Factors
QUIZ – choose the correct answer
• How many kind of UPS are there?
-1
-3
-2
-4
• Line conditioner level the AC to reduce
- brownout
- spikes
- power
- voltage
• A faulty power supply can cause:
- Memory error
- data errors
- system hangs
- reboot
- it can damage a mother board or other components
• Device that are Energy Star-compliant go into
sleep mode, in which they use less than
- 35 watts of power
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- 30 watts of power
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Question
Questions?
Video ‘chapter 3/Replacing the power supply’
and now it’s time to practice
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