Lesson Plan
Course Title: Computer Maintenance
Session Title: Power Supplies
Lesson Duration: 180 Minutes
Performance Objective:
Upon completion of this assignment, students will be able to describe and demonstrate the
functionality of a PC power supply.
Specific Objectives:
• Understand what the PC power supply is.
• Understand how the power supply works.
• Know when and how to change out a PC power supply.
• Demonstrate how to check a computer’s power supply.
• Demonstrate how to remove and replace a power supply.
• Demonstrate an understanding of terminology and concepts related to PC power
supplies.
Preparation
TEKS Correlations:
130.273(C) (4) (G)
describe the architecture of various computer systems;
130.273(C) (5) (A)
demonstrate safe use of equipment in computer technologies such as hand and power
tools;
130.273(C) (5) (B)
employ available reference documentation such as tools, materials, and Internet sources
to access information as needed;
130.273(C) (5) (C)
demonstrate proper handling and disposal of environmentally hazardous materials used
in computer technologies.
130.273(C) (6) (A)
use electronic test equipment to measure current, voltage, power, and resistance.
130.273(C) (6) (B)
describe digital circuits design.
Instructor/Trainer
References:
1. Cisco Systems Sponsored Curriculum: IT Essentials I: PC Hardware and Software,
Chapter 3: Assembling a Computer.
2. IDG Books Worldwide Inc., A+ Certification for Dummies, Chap. 8: Power.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
1
Instructional Aids:
1. PowerPoint presentation: Power Supplies.
2. Power Supply Word Search
3. Power Supply Word Search - KEY
4. Power Supply Worksheet
5. Power Supply Worksheet - KEY
6. PC Power Supply Exam
7. PC Power Supply Exam - KEY
Materials Needed:
1. Standard computer technician tool kit with wrist-strap [for each pair of students].
2. Copies of Word Search, Worksheet, and Lab Assignment [for each student].
Equipment Needed:
1. A projection system to display the PowerPoint presentation [PC w/monitor or projector]
2. One PC for disassembling for each two students, for labs.
3. [Optional] Stand-alone AT and ATX motherboards and power supplies (to demonstrate
differences in connections).
Learner
1. Students should read the appropriate curriculum material for how to assemble and
disassemble a PC [depending on the text/curriculum being used for this course]. This
lesson can be taught with only the PowerPoint presentation, and the equipment outlined
above.
Introduction
MI
Introduction (LSI Quadrant I):
The power supply is possibly the number one most likely component to fail in a PC.
Understanding how power supplies function is therefore a key component in the
training for a computer technician.
AT power supplies have two connectors [P8 and P9] for connecting to the
motherboard. Does anyone know how to tell if these two connectors are oriented
properly?
The P8 and P9 connectors are oriented correctly if all four of the black wires, or
grounds (two on each plug), are together in the middle.
Outline
MI
Outline (LSI Quadrant II):
Instructor Notes:
I.
Provide the word
search as a warmup and introduction
to the topic.
Have the students complete the Power Supply Word
Search.
II. Introduce the students to the power supply of a PC,
including
A. Power supply warnings
B. The anatomy of the power supply
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
2
C. The power supply cooling fan
1. Baby AT
2. ATX
D. Power supply and expandability
E. Converting power
F. Connecting the power
1. Baby AT
2. ATX
G. Discussion on when to unplug or not
Provide students
with the worksheet
to complete during
the presentation.
III. Give a demonstration of the power supply connections
(Baby AT and ATX)
IV. Students complete the lab demonstration including
A. Lab 1: Remove and Reinstall a Power Supply
Application
MI
Guided Practice (LSI Quadrant III):
1. The teacher shows and demonstrates each lab principle.
2. The teacher maintains direct supervision in the lab, providing guidance when
warranted.
MI
Independent Practice (LSI Quadrant III):
1. Students work in pairs on lab assignments, demonstrating their skills in
identifying and discussing the various lab requirements and results.
Summary
MI
Review (LSI Quadrants I and IV):
1. Ask the students summary questions:
a. What are the two types of power supplies? [Baby AT and ATX]
b. What output voltages are common for an ATX power supply? [+5V, -5V,
+12V, -12V and +3.3V]
c. What is the difference in the air flow of the power supply fans on the Baby
AT and ATX power supply? [The baby AT blows air out of the case; the
ATX sucks air into the case, pressurizing the case]
2. Revisit the steps the students went through to reinstall the power supply.
Evaluation
MI
Informal Assessment (LSI Quadrant III):
1. The teacher will monitor student progress during independent practice and
provide independent re-teach/redirection as needed.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
3
MI
Formal Assessment (LSI Quadrant III, IV):
Administer the Power Supply Exam.
Extension
MI
Extension/Enrichment (LSI Quadrant IV):
Students that have mastered the lab assignments, can peer-tutor students [one-onone] that are having difficulty with the disassembly or assembly of the PC.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
4
Icon
MI
Verbal/
Linguistic
Logical/
Mathematical
Visual/Spatial
Musical/
Rhythmic
Bodily/
Kinesthetic
Intrapersonal
Interpersonal
Naturalist
Existentialist
Teaching Strategies
Personal Development
Strategies
Lecture, discussion, journal
writing, cooperative learning,
word origins
Reading, highlighting, outlining,
teaching others, reciting information
Problem-solving, number
games, critical thinking,
classifying and organizing,
Socratic questioning
Mind-mapping, reflective
time, graphic organizers,
color-coding systems,
drawings, designs, video,
DVD, charts, maps
Use music, compose songs
or raps, use musical
language or metaphors
Organizing material logically, explaining
things sequentially, finding patterns,
developing systems, outlining, charting,
graphing, analyzing information
Developing graphic organizers, mindmapping, charting, graphing, organizing
with color, mental imagery (drawing in
the mind’s eye)
Use manipulatives, hand
signals, pantomime, real life
situations, puzzles and board
games, activities, roleplaying, action problems
Reflective teaching,
interviews, reflective listening,
KWL charts
Cooperative learning, roleplaying, group brainstorming,
cross-cultural interactions
Natural objects as
manipulatives and as a
background for learning
Socratic questions, real life
situations, global
problems/questions
Creating rhythms out of words, creating
rhythms with instruments, playing an
instrument, putting words to existing
songs
Moving while learning, pacing while
reciting, acting out scripts of material,
designing games, moving fingers under
words while reading
Reflecting on personal meaning of
information, studying in quiet settings,
imagining experiments, visualizing
information, journaling
Studying in a group, discussing
information, using flash cards with
others, teaching others
Connecting with nature, forming study
groups with like-minded people
Considering the personal relationship to
the larger context
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
5
Name ______________________________________________ Date _____________
PC Power Supply – Word Search
Locate each of the words in the word search below. You should become familiar with
each of the terms. The words can go forward, backward, up, down, or diagonal.
During the Power Supply lesson, pay attention to learn the meaning of each of these
words.
S
V
S
S
A
Q
Z
F
T
X
O
D
X
Q
L
•
•
•
•
•
•
•
•
•
•
•
T
I
D
A
R
A
F
O
R
C
I
M
J
M
D
P
G
Z
H
J
I
V
E
Z
D
Q
H
K
K
R
F
O
D
C
H
V
D
M
O
C
C
R
B
T
A
E
E
W
U
D
P
H
E
G
A
T
L
O
V
O
K
N
L
E
P
Q
V
Z
N
C
Y
R
U
G
B
B
A
E
E
R
L
R
H
G
I
S
B
N
H
R
R
F
S
U
C
S
J
O
C
I
T
E
O
Q
E
I
G
G
X
P
T
U
U
T
T
X
P
R
S
H
W
N
C
T
W
C
R
P
T
I
I
P
C
T
T
X
I
T
P
F
D
K
I
P
J
C
W
R
T
O
R
L
A
L
C
L
E
H
C
L
B
A
S
A
M
U
O
R
H
T
N
G
I
E
I
Y
C
P
W
L
A
O
Z
G
P
D
F
L
V
N
T
Q
F
A
Y
J
C
Y
S
T
I
U
C
R
I
C
Y
Y
U
C
power supply
voltage
circuits
cooling fan
capacitor
switch
cpu
watts
microfarad
electricity
motherboard
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
6
Name ________________________________________ Date _____________
PC Power Supply – Word Search- Key
Locate each of the words in the word search below. You should become familiar with
each of the terms. The words can go forward, backward, up, down, or diagonal.
During the Power Supply lesson, pay attention to learn the meaning of each of these
words.
S
V
S
S
A
Q
Z
F
T
X
O
D
X
Q
L
•
•
•
•
•
•
•
•
•
•
•
T
I
D
A
R
A
F
O
R
C
I
M
J
M
D
P
G
Z
H
J
I
V
E
Z
D
Q
H
K
K
R
F
O
D
C
H
V
D
M
O
C
C
R
B
T
A
E
E
W
U
D
P
H
E
G
A
T
L
O
V
O
K
N
L
E
P
Q
V
Z
N
C
Y
R
U
G
B
B
A
E
E
R
L
R
H
G
I
S
B
N
H
R
R
F
S
U
C
S
J
O
C
I
T
E
O
Q
E
I
G
G
X
P
T
U
U
T
T
X
P
R
S
H
W
N
C
T
W
C
R
P
T
I
I
P
C
T
T
X
I
T
P
F
D
K
I
P
J
C
W
R
T
O
R
L
A
L
C
L
E
H
C
L
B
A
S
A
M
U
O
R
H
T
N
G
I
E
I
Y
C
P
W
L
A
O
Z
G
P
D
F
L
V
N
T
Q
F
A
Y
J
C
Y
S
T
I
U
C
R
I
C
Y
Y
U
C
power supply
voltage
circuits
cooling fan
capacitor
switch
cpu
watts
microfarad
electricity
motherboard
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
7
Name __________________________________________ Date _____________
Computer Maintenance – Power Supplies Worksheet
1. The current in a standard wall outlet is _________ power.
2. The computer runs on ________ power.
3. What component converts power from the wall outlet to the type of current needed by
the computer?
4. How does the PC Power Supply take an incoming 110 volts and produce an output of 12
volts?
5. What are two problems that can result from having a bad power supply?
a. ______________________________________
b. ______________________________________
6. What component can store electricity even when the power is off?
7. What are the 4 primary components of a power supply?
a. ______________________________
b. ______________________________
c. ______________________________
d. ______________________________
8. What is the purpose of the power supply fan?
9. How does the Baby AT form cool the motherboard?
10. How does the ATX form cool the motherboard?
11. When the power supply is form factor AT, why should the PC be plugged in when
working on it?
12. When the power supply is form factor XAT, why should the PC be unplugged when
working on it?
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
8
Name ________________________________________ Date _____________
Computer Maintenance – Power Supplies Worksheet
KEY
1. The current in a standard wall outlet is
2. The computer runs on
DC
AC
power.
power.
3. What component converts power from the wall outlet to the type of current needed by
the computer?
the power supply
4. How does the PC Power Supply take an incoming 110 volts and produce an output of 12
volts?
by switching a pass-through charge on and off to adjust the voltage
5. What are two problems that can result from having a bad power supply?
a. Could cause hard disks to develop bad sectors
b. Could affect memory to cause what seem like software bugs
6. What component can store electricity even when the power is off?
capacitor
7. What are the 4 primary components of a power supply?
a. power cord
b. pass-through connector
c. power switch
d. 110V / 220V selector switch
8. What is the purpose of the power supply fan?
to force airflow through the computer case, and over the motherboard and
electronic components
9. How does the Baby AT form cool the motherboard?
by pulling air out of the case through the fan
10. How does the ATX form cool the motherboard?
by sucking air into the case
11. When the power supply is from factor AT, why should the PC be plugged in when
working on it?
The connection provides a positive ground.
12. When the power supply is form factor ATX, why should the PC be unplugged when
working on it?
The mother board is hot and will have power going to it, so the power must be
disconnected.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
9
Name ______________________________________________ Date _____________
Computer Maintenance – Power Supply Exam
1. What is the maximum output voltage produced by a power supply for a PC’s usage?
A. 5V AC
B. 5V DC
C. 12V AC
D. 12V DC
2. The PC power supply is known as which kind of power supply?
A. closed
B. switching
C. capacitor
D. conversion
3. How much input voltage do most power supplies accept?
A. 110V AC
B. 110V DC
C. 220V AC
D. 110V and 220V AC
4. Never “test” a power supply without doing which of the following?
A. ensuring that there is some demand
B. ensuring that there is some power
C. ensuring that there is no demand
D. ensuring that there is no power
5. A bad power supply often
A. creates problems that are solvable through software applications
B. creates problems that can only be pointed to the power supply
C. creates problems that are hard to pin on the power supply
D. creates problems that are easy to pin on the power supply
6. Which of the following internal power supply components is dangerous to touch?
A. Microfarad capacitor
B. Inverse capacitor
C. Macro capacitor
D. Fuse capacitor
7. Which of the following are primary power supply components?
A. power tester; pass-through connectors; power switch; voltage selector switch
B. power cord; pass-through connectors; power switch; voltage selector switch
C. power cord; pass-through connectors; power tester; voltage selector switch
D. power cord; power tester; power switch; voltage selector switch
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
10
8. Which of the following are the two popular form factors for power supplies?
A. AT and XT
B. ATX and XT
C. ATX and AT
D. AT and XTA
9. All of the following describes attributes of the ATX power supply except:
A. Cools the system by sucking air into the case
B. Power supply blows air straight onto the processor
C. Helps keep the case clean by pressurizing the inside of the case
D. You can feel the air blowing out of the fan in the back of the power supply
10. How are power supplies rated?
A. Watt capacity
B. Volt capacity
C. Watt usage
D. Volt usage
11. Which of the following is NOT a description of what a power supply does?
A. It converts AC to DC
B. It provides proper AC voltage to the CPU
C. It must provide a variety of voltages at different strengths
D. It must manage some power-related signals for the motherboard
12. The Baby AT power supply has which of the following motherboard connector(s)?
A. Two 20-wire connectors
B. Single 20-wire connector
C. Two 6-wire connectors
D. Single 6-wire connector
13. The ATX power supply has which of the following motherboard connector(s)?
A. Two 20-wire connectors
B. Single 20-wire connector
C. Two 6-wire connectors
D. Single 6-wire connector
14. How should AT power supply P8 and P9 connectors be connected to the
motherboard?
A. The P8 connector should be towards the back of the computer.
B. The P9 connector should be plugged into the motherboard first.
C. The black wires of P8 and P9 should be in the middle of the connector.
D. The red wires of P8 and P9 should be in the middle of the connector.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
11
15. Which of the following types of power plugs is used to connect most hard drives and
CD-ROMs?
A. Molex connector
B. Simplex connector
C. Serial connector
D. Berg connector
16. Which of the following types of power plugs is used to connect most floppy drives?
A. Molex connector
B. Simplex connector
C. Serial connector
D. Berg connector
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
12
Name ________________________________________ Date _____________
Computer Maintenance – Power Supply Exam Key
1. What is the maximum output voltage produced by a power supply for a PC’s usage?
A. 5V AC
B. 5V DC
C. 12V AC
D. 12V DC
2. The PC power supply is known as which kind of power supply?
A. closed
B. switching
C. capacitor
D. conversion
3. How much input voltage do most power supplies accept?
A. 110V AC
B. 110V DC
C. 220V AC
D. 110V and 220V AC
4. Never “test” a power supply without doing which of the following?
A. ensuring that there is some demand
B. ensuring that there is some power
C. ensuring that there is no demand
D. ensuring that there is no power
5. A bad power supply often
A. creates problems that are solvable through software applications
B. creates problems that can only be pointed to the power supply
C. creates problems that are hard to pin on the power supply
D. creates problems that are easy to pin on the power supply
6. Which of the following internal power supply components is dangerous to touch?
A. Microfarad capacitor
B. Inverse capacitor
C. Macro capacitor
D. Fuse capacitor
7. Which of the following are primary power supply components?
A. power tester; pass-through connectors; power switch; voltage selector switch
B. power cord; pass-through connectors; power switch; voltage selector
switch
C. power cord; pass-through connectors; power tester; voltage selector switch
D. power cord; power tester; power switch; voltage selector switch
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
13
8. Which of the following are the two popular form factors for power supplies?
A. AT and XT
B. ATX and XT
C. ATX and AT
D. AT and XTA
9. All of the following describes attributes of the ATX power supply except:
A. Cools the system by sucking air into the case
B. Power supply blows air straight onto the processor
C. Helps keep the case clean by pressurizing the inside of the case
D. You can feel the air blowing out of the fan in the back of the power
supply
10. How are power supplies rated?
A. Watt capacity
B. Volt capacity
C. Watt usage
D. Volt usage
11. Which of the following is NOT a description of what a power supply does?
A. It converts AC to DC
B. It provides proper AC voltage to the CPU
C. It must provide a variety of voltages at different strengths
D. It must manage some power-related signals for the motherboard
12. The Baby AT power supply has which of the following motherboard connector(s)?
A. Two 20-wire connectors
B. Single 20-wire connector
C. Two 6-wire connectors
D. Single 6-wire connector
13. The ATX power supply has which of the following motherboard connector(s)?
A. Two 20-wire connectors
B. Single 20-wire connector
C. Two 6-wire connectors
D. Single 6-wire connector
14. How should AT power supply P8 and P9 connectors be connected to the
motherboard?
A. The P8 connector should be towards the back of the computer.
B. The P9 connector should be plugged into the motherboard first.
C. The black wires of P8 and P9 should be in the middle of the connector.
D. The red wires of P8 and P9 should be in the middle of the connector.
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
14
15. Which of the following types of power plugs is used to connect most hard drives and
CD-ROMs?
A. Molex connector
B. Simplex connector
C. Serial connector
D. Berg connector
16. Which of the following types of power plugs is used to connect most floppy drives?
A. Molex connector
B. Simplex connector
C. Serial connector
D. Berg connector
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
15
Computer Maintenance – Power Supply Lab
Lab 1: Remove and Reinstall a Power Supply
Student Name: _____________________________ Date: __________
Objectives:
• Remove a Power Supply
• Verify the correct orientation of connector cables
• Reinstall a Power Supply
Background:
In this procedure you will start a computer to verify that it is operating properly.
Then you will remove the power supply from the computer. You will go through
all the steps of removal. Upon completion of the removal of the power supply you
will reinstall the power supply in the computer and reboot the system. You will go
through all the steps of reinstallation.
Resources:
The following resources will be required:
• PC Tool Kit
• Anti Static Wrist Strap
• Personal computer (PC)
• Operating system installed (MSDOS, MS Windows 95/98/2000/Millennium)
NOTE: This lab assumes an AT type PC is used. If an ATX type PC is used some
modifications might need to be made in the step-by-step procedures. I.e. the switch
mount on the front of the PC will not have to be removed for ATX and there is only a
single connector on the motherboard etc.
Step 1 – Booting up the computer
1. Push the power button to turn the computer on. The computer should do a
quick memory test (some numbers will count on the screen)
2. The computer will boot up to a MS DOS screen and should show a “C”
prompt that should look something like: C:>
3. Push the power button to turn the computer off
Step 2 – Remove system case
1. Unplug power cord from power supply
2. Remove screws from back of case
Step 3 – Identify type of power supply (check type below)
1. Power supply is an AT type
2. Power supply is an ATX type
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
16
Step 4 – Disconnect power supply connections
1. Disconnect the power connector from the hard drive
2. Disconnect the power connector from the CD-ROM
3. Disconnect the power connector from the floppy drive
4. Disconnect the power connector from the tape drive
5. Disconnect the power connectors from the system board [notice the
orientation]
Step 5 – Remove Power Supply
1. Remove switch mounting screw from switch mount at front of chassis [if AT
power supply]
2. Remove four screws from back of chassis that hold the power supply onto
the chassis
3. Remove the power supply
You have now successfully removed a power supply from a PC. The next portion
of this lab will concentrate on reinstalling the power supply.
Step 6 – Install Power Supply
1. Place the power supply back into the chassis
2. Insert four screws through back of chassis that hold the power supply onto
the chassis
3. Attach switch mounting screw through switch mount at front of chassis [if
AT power supply]
Step 7 – Connect power supply connections
1. Connect the power connectors to the system board [notice the orientation]
2. Connect the power connector to the CD-ROM
3. Connect the power connector to the floppy drive
4. Connect the power connector to the hard drive
Step 8 – Reinstall system case
1. Replace the cover of the computer.
2. Replace the cover screws.
3. Plug in the power cord.
Step 9 – Booting up the computer
1. Push the power button to turn the computer on. The computer should do a
quick memory test (some numbers will count on the screen)
2. The computer will boot up to a MS DOS screen and should show a “C”
prompt that should look something like: C:>
3. Push the power button to turn the computer off
IT: Computer Maintenance: Power Supplies Lesson Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
17