Transcript Getting Started with Support

Course ILT
Electricity and power systems
Unit objectives
 Measure and describe the
characteristics of electricity
 Identify static electricity and follow
ESD safe practices when working with
computers
 Describe the purpose and features of
power supplies and install a new
power supply into a PC
 Troubleshoot faulty power supplies
Course ILT
Topic A
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Topic A: Electricity and electronics
Topic B: Static electricity
Topic C: Power supplies
Topic D: Power supply troubleshooting
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Electricity characteristics
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Voltage
Current
Alternating or direct current
Resistance and impedance
Power and energy
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Activity A-1
Examining the characteristics
of electricity
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Electrical safety
 Current can kill
 The 1–10–100 rule
 Calculating current
V=i*r
 Resistance of the human body
Course ILT
Safety precautions
Don’t touch exposed contacts
Touch only insulated handles of tools
Leave covers on equipment
Work one-handed
Don’t stick things into electrical
sockets
 Remove jewelry, watches, etc.
 Keep hands clean and dry
 Don’t work in wet surroundings
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Activity A-2
Considering electrical safety
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Digital multimeter
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Analog multimeter
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Using a multimeter
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Measuring resistance
Measuring voltage
Measuring current
Measuring continuity
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Activity A-3
Measuring electrical values
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Topic B
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Topic A: Electricity and electronics
Topic B: Static electricity
Topic C: Power supplies
Topic D: Power supply troubleshooting
Course ILT
Static electricity
 Build up of charges
 Static dangers
 Discharge voltages
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3,000+ volts to feel
8,000+ volts to see spark
35,000 volts on a dry day on carpet
1,000 volts can damage electronics
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Prevent static build-up
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Don’t shuffle your feet
Increase the humidity
Keep yourself grounded
Wear cotton, not synthetics
Remove carpeting
Use air ionization system
Prevent static discharge
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 Equalize charge differences safely
– Unplug the equipment
– Touch its metal chassis or power supply
 Keep yourself and equipment
connected
– Wrist straps and anti-static mats
– Static-safe bags
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Static wrist strap
Typical internal components
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CD-ROM drive
Power supply
CPU / fan
Adapter card
Motherboard
Hard drive
Slide catches
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Slide catch, move to open side of case
Determining which side to open
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Open this side to access components
Ports and connectors attached to motherboard
Removable front cover
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Alignment holes
Alignment posts
Spring catches
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Activity B-1
Opening the computer case while
following proper ESD precautions
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Topic C
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Topic A: Electricity and electronics
Topic B: Static electricity
Topic C: Power supplies
Topic D: Power supply troubleshooting
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A PC power supply
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Voltage selection switch
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Typical power requirements
Motherboard
30 W
Memory
10 W / 128 MB
CPU
65 W or more
Hard drive
5 – 15 W
CD-ROM drive
10 – 20 W
Floppy drive
5 – 10 W
Adapter card
5 – 30 W
Course ILT
Standard outputs
+3.3 V
14 A
AGP video cards, motherboard
-5 V
0.3 A
ISA bus adapter cards
+5 V
30 A
Motherboard, CD/DVD drives, hard
drives, PCI adapter cards, Pentium III
and earlier processors
+5 V
0.85 A
“Soft power” switch
-12 V
1A
Older network adapters and serial
ports
+12 V
12 A
CD/DVD drives, hard drives, Pentium
4 and Athlon processors,
motherboard
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Power_Good signal
 Signals CPU that power is stable and
sufficient
 +5 V over specific wire
 Must arrive at correct time
Peripheral power connector
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 “Molex” connector
Floppy power connector
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 “Berg” connector
SATA power connector
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 New, for Serial ATA drives
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Wire colors
 Yellow = +12 V
 Red = +5 V
 Black = ground
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Motherboard power connectors
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Power supply form factors
ATX/NLX
150 x 140 x 86
millimeters
486 and
Pentium PCs
First with softpower switch
and 3.3V
SFX
100 x 125 x 63.5
millimeters
Pentium PCs
No -5 V output
for ISA cards
WTX
150 x 230 x 86
(single fan)
224 x 230 x 86
(double fan)
Pentium PCs
No -5 V output
for ISA cards
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Activity C-1
Examining a power supply
and connectors
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Topic D
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Topic A: Electricity and electronics
Topic B: Static electricity
Topic C: Power supplies
Topic D: Power supply troubleshooting
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Troubleshooting symptoms
 Computer fails to boot when powered
on, but boots after pressing Ctrl + Alt +
Delete
 Computer intermittently stops working
or reboots
 You don’t have sufficient power
connectors to connect all the devices
you want to install
 Computer fails to boot at all, with no
lights or beeps; fans don’t start
 Computer fails to boot, but fans start
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Activity D-1
Troubleshooting power supply problems
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Unit summary
 Measured and described the
characteristics of electricity
 Identified static electricity and followed
ESD safe practices when working with
computers
 Described the purpose and featurse of
power supplies; and installed a new
power supply into a PC
 Resolved faulty power supply
problems