Transcript A+ Instructor Manual Ch 3

Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting Essential
Hardware
Chapter 3
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Overview
Fourth Edition (Exam 220-802)
• In this chapter, you will learn how to
– Troubleshoot CPUs
– Troubleshoot RAM
– Troubleshoot BIOS and motherboards
– Troubleshoot power supplies
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting CPUs
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Troubleshooting CPUs
Fourth Edition (Exam 220-802)
• Overheating—can cause system to not
start or to lock up. Newer CPUs will
usually shut themselves down before
overheating.
– Too much heat dope (thermal paste) can impede
the flow of heat from the CPU to the heat sink and
cause the CPU to heat up rapidly.
– Not enough thermal paste can cause the CPU to
heat up and shut down.
– Faulty fan power connection can cause the CPU to
heat up and shut down.
– Heating may take longer and cause problems after
boot and OS load
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting CPUs
(continued)
– Environmental heat/lack of adequate ventilation
can cause CPU heat-up and shutdown
• Catastrophic failure
– May cause Windows Stop error (Blue Screen
of Death)
– May cause PC to shut down or go black
– May burn up components
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting CPUs
(continued)
Figure 1: Blue Screen of Death
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting RAM
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Memory Errors
Fourth Edition (Exam 220-802)
• Memory errors can include
–
–
–
–
–
Parity errors
ECC error messages
System lockups
Page faults
Other error screens in Windows
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Memory Errors (continued)
Fourth Edition (Exam 220-802)
• Write down memory error addresses.
– If the error returns with the same address each
time, it is likely a RAM stick failure.
• If the error address changes, it is likely
not a RAM failure.
• System lockups and page faults often
indicate RAM problem.
• RAM and parity errors can trigger a nonmaskable interrupt (NMI) that results in
the Blue Screen of Death (BSoD).
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Memory Errors (continued)
Fourth Edition (Exam 220-802)
Figure 2: Windows error message
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Memory Errors (continued)
Fourth Edition (Exam 220-802)
• Not all intermittent errors are caused by
bad RAM
– Dying power supply, electrical interference, and
buggy applications or hardware can also produce
intermittent errors.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Testing RAM
Fourth Edition (Exam 220-802)
• Several RAM testing devices are
available, but many are expensive.
• Can replace one stick at a time until
problems disappear.
• Use a software-based tester such as
Memtest86.
• Windows 7 includes the Memory
Diagnostics Tool, which can
automatically scan your computer’s RAM
when you encounter a problem.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Testing RAM (continued)
Fourth Edition (Exam 220-802)
Figure 3: Memtest86 in action
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Power-on Self Test (POST)
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
ROM Initiates the POST
Process
• Upon boot, the ROM initiates the POST
process.
• The POST routine sends out a message
to all assumed components to initiate
self-tests.
– This determines whether the components are
working properly. The quality of POST diagnostics
is determined by the component.
• If a component fails self-diagnostics, the
POST process halts and sends an error
message.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Beep Codes
Fourth Edition (Exam 220-802)
• Before and during the video test: beep
codes
• If video is missing or faulty, you’ll hear
one long beep followed by three short
beeps.
• If RAM is missing or faulty, you’ll hear a
rather alarming beeping/buzzing that
will repeat as long as the computer is on.
• If the POST completes successfully,
you’ll hear one or two short beeps.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Text Errors
Fourth Edition (Exam 220-802)
• Once the video is determined to be good,
errors can be displayed.
• Errors are usually displayed in clear text,
though they can sometimes be rather
cryptic.
Figure 4: POST text error messages
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Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
POST Cards
Fourth Edition (Exam 220-802)
• The small expansion card installs into an
available slot
– Used to monitor the POST and identify whether a
piece of hardware is causing startup issues
• Note the light-emitting diode (LED)
display to see what device POST is
currently checking
– Refer to the two-digit hex code on the LED display
to determine the faulty POST code
• Look up the code in the companion
manual—it can help identify the faulty
component
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
POST Cards (continued)
Fourth Edition (Exam 220-802)
• If the PC passes POST, the problem is
more likely a software problem
• POST cards used to be an essential tool
for techs
– Today they are rarely used, and then only on a
“dead” PC to determine at which level it’s dead
– If the POST card shows no reading, the problem is
before the POST and must be related to the CPU
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
POST Cards (continued)
Fourth Edition (Exam 220-802)
Figure 5: POST card in action
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
The Boot Process
Fourth Edition (Exam 220-802)
• The power supply checks for proper
voltage.
– If the proper voltage is found, the power supply
sends a signal through the power-good wire.
– This awakens the CPU, which in turn sends a builtin memory address, which is the first line of the
POST program on the system ROM.
• The ROM begins the POST routines.
• Once the POST is passed, the ROM begins
the boot process (the bootstrap loader)
by looking for an operating system
according to the CMOS settings.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
The Boot Process (continued)
Fourth Edition (Exam 220-802)
Figure 6: CMOS boot order
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
The Boot Process (continued)
Fourth Edition (Exam 220-802)
• The CMOS settings tell it which device to
try to boot from.
– It looks at the boot sector of that device (floppy,
CD-ROM, hard drive, etc.) and tries to load an
operating system.
• Once the boot process begins, control is
handed over to the operating system.
• Some BIOSs allow the PC to use a
preboot execution environment (PXE).
– A PXE enables you to boot a PC without any local
storage by retrieving an OS from a server over a
network.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Care and Feeding of BIOS
and CMOS
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Losing CMOS Settings
Fourth Edition (Exam 220-802)
• The battery provides continuous trickle
charge to hold data. It also keeps the
clock running.
• If the battery dies or is removed, all data
is lost and the system returns to factory
defaults.
• Common errors
–
–
–
–
CMOS configuration mismatch
CMOS date/time not set
No boot device available
CMOS battery state low
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Losing CMOS Settings
(continued)
• Common reasons for losing CMOS data
–
–
–
–
–
–
Pulling and inserting cards
Touching the motherboard
Dropping something on the motherboard
Dirt on the motherboard
Faulty power supplies
Electrical surges
• If settings keep resetting, replace the
battery.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Losing CMOS Settings
(continued)
Figure 7: A CMOS battery
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Flashing ROM
Fourth Edition (Exam 220-802)
• Flash ROM chips can be reprogrammed.
• Download the program from the
manufacturer and follow the
instructions.
• Typically insert a removable disk of some
sort (usually a USB thumb drive)
containing an updated BIOS file.
• Only flash the BIOS if necessary.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Flashing ROM (continued)
Fourth Edition (Exam 220-802)
Figure 8: ROM-updating program for an ASUS motherboard
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting Motherboards
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Troubleshooting Symptoms
Fourth Edition (Exam 220-802)
• Catastrophic failure
– System will not boot.
– Although uncommon, most motherboards will fail
(if they’re going to) within the first 30 days due to
manufacturing defects, called burn-in failure.
– Electrostatic discharge is the other most common
cause.
– To fix, replace the motherboard.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
More Troubleshooting Symptoms
Fourth Edition (Exam 220-802)
• Component failure
– Intermittent problems
– Examples include a hard drive that shows up in
CMOS but not in Windows
– Most common causes are electrical surges and ESD
– Sometimes a BIOS upgrade may solve this problem
if the issue is lack of BIOS support for a newer
technology
– Fixes include replacing the component with an
add-on card or flashing the BIOS
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
More Troubleshooting Symptoms
(continued)
• Ethereal symptoms
– Things just don’t work all the time.
– PC reboots itself for no apparent reason.
– Blue Screens of Death appear as the computer
crashes.
– Causes include faulty components, buggy device
drivers or application software, slight corruption of
the operating system, and power supply problems.
– Fixes include flashing the BIOS or replacing the
motherboard.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Techniques
Fourth Edition (Exam 220-802)
• Isolate the problem by eliminating
potential factors.
• Check, replace, verify good component.
– If the hard drive doesn’t work, try a different hard
drive, or try the same hard drive with a different
motherboard.
• If the new hard drive works, you know it wasn’t the
motherboard.
• If the same hard drive with a different motherboard
works, you can suspect the motherboard.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Options
Fourth Edition (Exam 220-802)
• There are a couple of options for dealing
with a motherboard failure.
– Catastrophic failure: replace the motherboard.
– Component failure: consider an add-on card to
replace the device.
• Consider a BIOS update if the device issue is a
problem other than physical damage.
Figure 9: Adaptec PCIe SATA card
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fourth Edition (Exam 220-802)
Troubleshooting Power Supplies
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Troubleshooting Power Supplies
Fourth Edition (Exam 220-802)
• Power supplies fail in two ways
– Sudden death
• When the fan doesn’t turn and no voltage is
present
• Computer simply stops working
– Slowly over time
• Intermittent errors
• Output voltages may exceed specs (±10%)
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Lab – Power Supply Test
Fourth Edition (Exam 220-802)
1. Set the multimeter to
test DC.
2. Turn on the PC.
3. Put the black lead onto
any black wire
connection.
4. Put the red lead onto a
colored wire.
• 12 V ± 10 percent
– 10.8 to 13.2 V
– If readings are outside
tolerance and symptoms
exist, replace power
supply.
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Figure 10: Testing one of the 5-V DC
connections
• 5V ± 10 percent
– 4.5 to 5.5 V
• 3.3 V ± 10 percent
– 2.97 to 3.63 V
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Power Supply Test
Fourth Edition (Exam 220-802)
• Power supplies need a load
– Plug into motherboard
– Plug into tester
• Check power switches
– If faulty, can turn on
with motherboard jumper
Figure 11: ATX power supply tester
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
When Power Supplies Die Slowly
Fourth Edition (Exam 220-802)
• Intermittent problems
– Sometimes occur, sometimes don’t
– You could measure voltage now and it’s good;
ten minutes later, system crashes
• A dying power supply can cause
– Random lockups and reboots
– Sporadic boot-up difficulties
• When you encounter intermittent
symptoms, consider replacing the
power supply
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fuses and Fire
Fourth Edition (Exam 220-802)
• Circuit breakers are heat-sensitive
– Sense when amperage exceeds threshold
– Breaks the circuit to stop flow of electricity
• Fuses blow for a reason
– Power supply is malfunctioning
– As a designed safety precaution, fuses blow
(break) to stop circuit
• Alternative is a possible fire
© 2013 The McGraw-Hill Companies, Inc. All rights reserved
Mike Meyers’ CompTIA A+®
Guide to 802:
Managing and
Troubleshooting PCs
Fire Extinguishers
Fourth Edition (Exam 220-802)
• Class A
– Ordinary combustibles such as paper and wood
• Class B
– Flammable liquids such as gasoline
• Class C
– Live electrical equipment
• Use only Class C extinguishers on
electrical fires
© 2013 The McGraw-Hill Companies, Inc. All rights reserved