A+ Guide to Hardware:
Managing, Maintaining, and
Troubleshooting, Sixth
Edition
Week 5
All About Motherboards
Objectives
• Learn about the different types of motherboards and
how to select one
• Learn how to support and configure a motherboard
• Learn how to install or replace a motherboard
• Learn how to troubleshoot a motherboard and
processor
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Motherboard Types and Features
• Motherboard
– Most complicated computer component
– One of the first items to consider when building a
computer
• Consider the following when purchasing a
motherboard:
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Form factor
Processor socket and chipset
Buses and number of bus slots
Other connectors, slots, and ports
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Motherboard Form Factors
• Determines motherboard size, features
– Compatible with power supplies, cases, processors,
expansion cards
• Most popular
– ATX, MicroATX, and Mini-ITX
• Mini-ITX is smaller than MicroATX and is also known as
ITX
• The following slides show examples of form factors
and comparisons of sizes and hold positions of
several form factors
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Figure 3-3 A Mini-ITX motherboard
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Table 3-1 Sockets for Intel processors used for desktop computers
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Processor Sockets
• Processor socket – determines which processors a
board can support
– Socket holds Intel or AMD processor
• Sockets for Intel processors
– Intel makes several Itanium and Xeon processors
designed for servers
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Processor Sockets
• Sockets and processor use different methods to
make contacts between them:
– Pin grid array (PGA) socket
• Pins aligned in uniform rows around socket
– Land grid array (LGA)
• Uses lands (pads) rather than pins
• Examples of LGA sockets: LGA775 and LGA1366
– Flip-chip land grid array (FCLGA) socket
• Chip is flipped over so that the top of the chip is on the
bottom and makes contact with the socket
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Processor Sockets
• Sockets and processor use different methods to
make contacts between them (cont’d):
– Staggered pin grid array (SPGA)
• Pins staggered over socket
• Squeezes more pins into a small space
• Easily bent
– Ball grid array (BGA)
• Not really a socket
• Processor is soldered to the motherboard
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Figure 3-6 Socket LGA775 is the first Intel socket to use lands rather than pins
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Processor Sockets
• Zero insertion force (ZIF) sockets
– All current processor sockets
– Side lever lifts processor up and out of the socket
• Sockets for AMD Processors
– AMD uses the PGA socket architecture (desktops)
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Table 3-3 Sockets for AMD processors used for desktop computers
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Processor Sockets
• Match a processor to the socket and motherboard
– Refer to motherboard, processor compatibility
documentation
Figure 3-9 AMD Athlon 64 processor to be inserted into an AM2+ socket
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Buses and Expansion Slots
• Buses are like highway transportation systems
• Four types of cargo carried by a bus:
– Power, control signals, memory addresses, data
• Bus evolution
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Buses have evolved around data path and speed
Synchronous components work with clock cycle
Asynchronous components are out of step with CPU
Wait state: command to CPU to wait for slower device
Bus types: expansion, local, local I/O, local video
• Expansion buses are asynchronous components
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Table 6-3 Buses listed by throughput
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Figure 6-6 Four outdated bus connections on expansion cards
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Micro Cannel
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Later PC buses
• PS/2 series - Microchannel bus totally
redefined and patented
– IBM’s attempt to discourage clones; but
PS/2 not too successful
• EISA - Extended ISA
– industry (non-IBM) extension of ISA to 32bit data transfer
– still back-compatible
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VESA Board
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Buses and Expansion Slots
(continued)
• The PCI buses
– Intended to replace the 16-bit ISA bus
– Types: Conventional PCI, PCI-X, PCI Express
• On-board ports (integrated components)
– Examples: keyboard, mouse port, parallel printer, USB
• Internal connectors
– EIDE, floppy drive connector, serial ATA, SCSI, 1394
• Riser slots
– Audio/modem riser (AMR)
– Communication and networking riser (CNR)
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PCI
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PCI-Express
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Figure 6-10 How PCI Express connects to the chipset and processor
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Figure 6-12 An audio/modem riser slot can accommodate an
inexpensive modem riser card
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Hardware Configuration
• Three ways to configure the motherboard:
– DIP switches, jumpers, CMOS RAM
• Dual inline package (DIP) switch
– Has ON (binary 1) and OFF (binary 0) positions
– Reset DIP switch when adding or removing device
– Use pointed instrument other than graphite pencil
• Jumpers
– Retain setup or installation information
– Are opened and closed using jumper covers
– Typical setting: enabling/disabling keyboard power-up
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Figure 6-14 DIP switches are sometimes used to
store setup data on motherboards
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Figure 3-35 This group of three jumpers controls the BIOS configuration
Figure 3-36 BIOS configuration jumper settings
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Hardware Configuration (continued)
• CMOS RAM
– Also called clock/nonvolatile RAM (RTC/NVRAM)
– Stores most configuration for the motherboard
– Can be accessed without opening the case
• CMOS setup program
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Stored on a floppy disk or ROM BIOS chip
Access built-in program by pressing key during POST
Menus: Main, Advanced, Power, Boot, and Exit
Brand name PCs, such as IBM, have custom screens
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CMOS
http://bochs.sourceforge.net/techspec/CMOS-reference.txt
----------R37-------------------------------CMOS 37h - AMI WinBIOS - SETUP COLORS, PASSWORD SEED
Bitfields for AMI WinBIOS setup colors and password seed:
Bit(s) Description (Table C044)
7-4 password seed
3-0 WinBIOS/AMIBIOS setup color options
----------R37-------------------------------CMOS 37h - Quadtel HT12 BIOS 03.05.03 - EXTENDED MEMORY (high byte)
----------R373A-----------------------------CMOS 37h-3Ah - AMI 1990 Hyundai super-NB368S notebook - PASSWORD
Desc: encoded password, max 4 bytes.
----------R38-------------------------------CMOS 38h - PHOENIX - Second user defined hard disk (type 48) Write Precomp. LSB
Note: used only when PS/2 style password is NOT in effect.
----------R383D-----------------------------CMOS 38h-3Dh - AMI - Encrypted Password
----------R383F-----------------------------CMOS 38h-3Fh - ??? IBM PS/2 - Encrypted Password
Note: Initialized to 00h in all bytes. Will accept from 1-7 scan codes.
----------R39-------------------------------CMOS 39h - PHOENIX - Second user defined hard disk (type 48) Write Precomp. MSB
Note: used only when PS/2 style password is NOT in effect.
----------R3A-------------------------------CMOS 3Ah - PHOENIX - Second user defined hard disk (type 48) Parking Zone LSB
Note: used only when PS/2 style password is NOT in effect.
----------R3B-------------------------------CMOS 3Bh - PHOENIX - Second user defined hard disk (type 48) Parking Zone MSB
Note: used only when PS/2 style password is NOT in effect.
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BIOS Manufactures
• About 100 different manufactures
http://support.microsoft.com/kb/243909
• Common PC BIOS’s
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AMD
AMI – American Megatrends
ASUS
AWARD
Dell
GateWay
Intel
Phoenix
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Table 6-4 How to access CMOS setup
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Figure 6-18 CMOS Setup Main menu
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Using Setup BIOS To Configure a
Motherboard
• Change the boot sequence
– Might need to change boot sequence from hard
drive to DVD
– Unified Extensible Firmware Interface (UEFI) – new
standard slowly replacing BIOS
• Ability to boot from large disks (over 2 TiB) with a
GUID Partition Table, GPT.[12][13]
• CPU-independent architecture[12]
• CPU-independent drivers[12]
• Flexible pre-OS environment, including network
capability
• Modular design
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Using Setup BIOS To Configure a
Motherboard
• Configure onboard devices
– Enable/disable a port or group of ports
• View hard drive and optical drive information
• Processor and clock speeds
– Some motherboards allow changing the processor
speed and/or the memory multiplier
• Monitor temperatures, fan speeds, and voltages
• Intrusion detection
– Can enable event logging (logs when case is
opened)
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Using Setup BIOS To Configure a
Motherboard
• Power-on passwords
– Assigned in BIOS setup to prevent unauthorized
access to the computer and/or BIOS setup utility
– May be possible to set a supervisor and user password
• If both passwords are set, must enter a valid password
to boot the system
– How to set passwords varies depending on
motherboard and BIOS
• Some allow a System power-on password, which will
require a password be entered every boot
• A Setup power-on password only requires a password
be entered in order to access BIOS setup
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Using Setup BIOS To Configure a
Motherboard
• LoJack
– Technology embedded in the BIOS of many laptops
to protect a system against theft
– Must subscribe to service
– Software and BIOS work together to locate a laptop
whenever it connects to the Internet
• Drive Encryption and Drive Password Protection
– Some motherboards allow you to set a password in
order to access the hard drive
– Password kept on drive so that it still works even if
drive is moved to another computer
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Using Setup BIOS To Configure a
Motherboard
• TPM chip – Trusted Platform Module chip
– BitLocker Encryption in Windows 7/Vista works with
this chip
– Encryption key is kept on chip
– Assures that a drive cannot be used in another
computer
– Ensure that installed s/w can not be copies.
• Virtualization – implementation of s/w or h/w
through s/w, implementation is independent of
host.
– Virtualization must be enabled in BIOS setup for VM
software to work
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UEFI vs BIOS
• Essentially version 2.0 of the EFI standard.
– Unified Extendable Firmware Interface
• Initial BIOS requires 16 bit processor mode (Intel
CPUs running in 8088 mode, think 1980’s)
– Can only access 1M of memory
• When Windows takes over, drivers override this
limitation.
– Support for MBR can access boot disks only up to
1TB.
• Requires several boot loader stages, since loader is
tied to specific locations on the disk.
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UEFI Advantages
• Boot from large disk +2 TB
– Does not rely on boot sector, but able to detect the boot file on the
system partition.
• Independent of:
– CPU (ARM, Intel x86, Itanium others)
– CPU independent Drivers, OS does not need to know what CPU is
running.
– Network capability
• Support for GPT (GUID partition table)
– Supports any number of bootable partitions
– Disks sizes up to 2 Zb (8x270)
• Support for most graphic standards
• Fully backward compatible with BIOS
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Using Setup BIOS To Configure a
Motherboard
• Exiting the BIOS setup menus
– Most exit screens give several options
Figure 3-50 BIOS setup Exit menu
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Hardware Configuration (continued)
• Battery power to CMOS RAM
– Enables CMOS to hold data after the PC is turned off
– Setup information is lost if battery fails or disconnects
• Startup passwords in CMOS
– Stored in CMOS RAM and changed in setup screen
– Should be distinguished from OS passwords
• CMOS settings are specified in motherboard manuals
• Documentation of configuration settings
– Enables you to recapture lost or altered settings
– Should be labeled and stored in a safe place
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Figure 6-24 The coin cell is the most common type of CMOS battery
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Flashing ROM BIOS
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Programs stored in the ROM BIOS chip:
– CMOS setup program
– Startup BIOS that manages the startup process
– System BIOS that manages basic I/O functions
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Programs on ROM BIOS may need upgrades
Flashing: upgrading or refreshing ROM BIOS chip
Sources for ROM BIOS upgrades
– Manufacturer’s Web site
– http://www.esupport.com
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Figure 6-26 Intel displays a list of motherboard model
numbers that have a Flash BIOS upgrade available
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Motherboard Drivers
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Located on CD bundled with motherboard
Motherboard CD may also contain useful utilities
Drivers are periodically updated by manufacturer
Dealing with an unstable motherboard
– Check for updated drivers, especially chipset drivers
– Install updated drivers for non-functioning devices
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Replacing a Motherboard
• Overview of the replacement process
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1. Verify that you have selected the right motherboard
2. Determine the power configuration settings
3. Remove components to reach the old motherboard
4. Set any jumpers or switches on the motherboard
5. Install the processor and processor cooler
6. Install RAM into appropriate slots on motherboard
7. Install the motherboard
8. Attach cabling (case switches, power supply, drives)
9. Install the video card on the motherboard
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Replacing a Motherboard (continued)
• Overview of the replacement process (continued)
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10. Plug in PC and then attach monitor and keyboard
11. Boot the system and enter CMOS setup
12. Make sure the settings are set to default
13. Observe POST and verify that no error occurs
14. Check for conflicts with system resources
15. Install the motherboard drives
16. Install any other expansion cards and drives
17. Verify the system is up and running
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Preparing the Motherboard to Go Into
the Case
• Read the manual before preparing the motherboard
• Setting the jumpers
– First step in preparing the motherboard
– The manual explains jumper and DIP switch settings
– Information differs from one motherboard to the next
• Tasks performed after setting the jumpers
– Install the processor and cooler (Chapter 5)
– Install the memory modules (Chapter 7)
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Figure 6-27 BIOS configuration jumper settings
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Installing the Motherboard in the Case
• Overview of the eight general steps:
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1. Install the faceplate (I/O shield)
2. Install the standoffs (spacers)
3. Secure the motherboard in the case
4. Connect the power cord to the PI power connection
5. Connect 4-pin auxiliary power cord to motherboard
6. Connect the wire leads from front panel of case
7. Refer to manual to verify wire to pin connection
8. Connect USB connection (if present) to USB ports
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Completing the Installation
• Following the connection of cables and cords
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Install the video card
Plug in the keyboard and monitor
Turn the system on
Look out for errors during POST
Install drivers from CD bundled with motherboard
Verify operations
Make OS and CMOS adjustments as needed
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Troubleshooting the Motherboard and
Processor
• Field replaceable units (FRUs) on old motherboards
– CPU, RAM, RAM cache, ROM BIOS, CMOS battery
• FRU components on newer motherboards:
– CPU, RAM, CMOS battery, and motherboard itself
• POST reporting aids diagnosis
– Chapter 3 or manufacturer Web site describe codes
• A good tactic: replace a bad device with a new one
– Caveat: check voltage from power supply first
– If voltage is excessive, new part may be damaged
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Figure 6-40 The ROM BIOS manufacturer’s Web site is a
good source of information about beep codes
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Problems with Installations
• If CPU was added to working motherboard, check:
– Thermal paste between CPU and heat sink
– Fastening between cooler and motherboard frame
– Pins or lands on the socket and processor
• Things to check if new motherboard is not working:
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Whether the front cover of the case is installed
Whether the power switch on back of the case is on
Incorrect connections
Installation of CPU, thermal compound, and cooler
Installation of all motherboard drivers on the CD
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Problems with the Motherboard and
Processor
• Some symptoms of impending failure
– The system begins to boot but then powers down
– Intermittent Windows or hard drive errors occur
• First troubleshooting task to perform
– Update drivers of components not working
– Use support CD bundled with motherboard
• A few other tasks to perform if update does not work
– Change power saving features, such as sleep mode
– Check jumpers, DIP switches, CMOS settings
– Exchange the processor
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Summary
• Motherboard form factor drives selection of
motherboard
• Configurable components: bus, expansion slots, other
connectors
• Cargo carried by a computer bus: electrical power,
control signals, memory address, data
• Bus types: local, local video, local I/O, expansion
• The PCI bus was designed to replace the ISA bus
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Summary (continued)
• Three tools for configuring a motherboard: DIP
switches, jumpers, CMOS setup program
• The CMOS setup program is stored on a floppy disk
or ROM BIOS chip
• Document configuration settings for recovery needs
• Upgrade ROM BIOS using a technique called flashing
• Use POST reporting to help diagnose problems
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