Motherboard

Alternatively referred to as the mb, mainboard, mobo, mobd, backplane board, base board, main circuit board, planar board, system board, or a logic board on Apple computers. The motherboard is a printed circuit board that is the foundation of a computer, located at the bottom of the computer case. It allocates power to the CPU, RAM, and all other computer hardware components and allows them to communicate with one another.

Below is a graphic illustration of the ASUS P5AD2-E motherboard and some basic explanations of each of the major portions of the motherboard. Clicking on the image below gives you a larger more detailed version of the picture below.

Motherboard components

Below is a listing of links that describe each of the above mentioned motherboard components in additional detail. Links are listed in clockwise order going from the top-left corner of the image. Components not listed above or found on other motherboards are listed in the next section.

• Expansion slots (PCI Express, PCI, and AGP)
• 3-pin case fan connectors
• Back pane connectors
• Heatsink
• 4-Pin (P4) power connector
• Inductor
• Capacitor
• CPU Socket
• Northbridge
• Screw hole
• Memory slot
• Super I/O
• Floppy connection
• ATA (IDE) disk drive primary connection
• 24-pin ATX power Supply connector
• Serial ATA connections
• Coin cell battery (CMOS backup battery)
• RAID
• System panel connectors
• FWH
• Southbridge
• Serial port connector
• USB headers
• Jumpers
• Integrated circuit
• 1394 headers
• SPDIF
• CD-IN

Other motherboard components

Below is a listing of other motherboard components that are not shown in the above picture or have been part of older computer motherboards.

• BIOS
• Bus
• Cache memory
• Chipset
• Diode
• Dip switches
• Electrolytic
• Fuse
• Game port and MIDI header
• Internal speaker
• Keyboard controller
• LCC
• Network header
• Obsolete expansion slots (AMR, CNR, EISA, ISA, VESA)
• Obsolete memory slots (SIMM)
• Onboard LED
• Parallel port header
• PS/2 header
• Resistor
• RTC
• Serial port header
• Screw hole aka mounting hole
• SCSI
• Solenoid
• Voltage regulator
• Voltage regulator module (VRM)

Motherboard form factors

As computers advanced, so have motherboards. Below is a listing of the various motherboard form factors and additional information about each of these form factors including ATX the most commonly used motherboard form factor today.

• AT
• ATX
• Baby AT
• BTX
• DTX
• LPX
• Full AT
• Full ATX
• microATX
• NLX

Since there is a motherboard, is there a fatherboard?

No, there is no such thing as a fatherboard when talking about a computer. However, there is such a thing as a daughterboard.

Boot menu

When a computer is starting up, a user can access the boot menu by pressing one of several keyboard keys, including Esc, F10 or F12, depending on the manufacturer of the computer or motherboard. The specific key to press is usually specified on the computer's startup screen. The boot menu allows a user to select what device to load an operating system or application from as the computer is booting.

The boot menu can contain a number of different device options to boot to, including CD or DVD drives, hard drives, USB flash drives and a LAN (network). This allows a user to load up other operating systems or applications, even if the computer itself already has an operating system on it. This is also useful when trying to install a new operating system on a computer, and the user needs to load the installation application from a CD or DVD.

How to replace the CMOS battery

If your computer is losing its time or date settings, or you are receiving a message CMOS Read Error, CMOS checksum error, or CMOS Battery Failure, first try leaving the computer on for 24-hours. In some cases, this can charge the battery and resolve your problem. This fixes most CMOS battery issues on computers left without power for several months. If this does not resolve your problem follow the steps below.

Locate your CMOS battery

Caution: When inside your computer make sure you are aware of ESD and its dangers.

Open the computer case and find the battery on the computer motherboard, verify that it is accessible and can be removed. Today, most computers use a coin cell CMOS battery as shown in the picture.

Tip: Some CMOS batteries may be held down by a metal clip or bar. This clip just holds the battery in place and the battery can still be removed by sliding it under the clip. Do not bend this clip to get the battery out.

If you are unable to locate your CMOS battery refer to your motherboard or computer documentation or contact your computer manufacturer for additional assistance in locating it.

Note: With some computers you may need to disconnect cables, remove drives, or remove other parts of the computer to get full access to the CMOS battery.

Obtain battery information

Unfortunately, most manufacturers do not list the exact type and model of your CMOS battery; therefore, once you have located the battery, write down all information about the battery (Voltage, chemistry, wiring, and packaging). If possible, remove the battery and take it to the retail location.

Tip: The part number for this battery for most computers is CR2032.

• Additional buying information is on our battery buying tips page.

Removing the battery

Caution: When inside your computer make sure you are aware of ESD and all its potential dangers.

If your computer is using a coin cell battery removing the battery is relatively simple. Use your fingers to grab on the edge of the battery and pull it up and out of the container holding it. Some motherboards have a clip holding the battery down. If your computer has this clip you may need to use one hand to move the clip up and the other hand to pull the battery out.

Unfortunately, not all CMOS batteries are removable; some manufacturers only allow a replacement battery to be added. If your computer does not have a coin cell battery and you are not sure how to remove the battery refer to your motherboard or computer documentation or contact your computer manufacturer for additional assistance in removing the battery or how to insert a new replacement battery.

Users with computers that do not have removable batteries only options to install a new battery will most likely also need to set a jumper when adding the new battery into their computer.

Insert the new battery

After purchasing a new battery, remove the old battery and replace it with a new battery.

Enter CMOS values

Once the battery is replaced turn on the computer and resetting the CMOS values to the defaults. After the values have all been entered make sure to save the settings before exiting. Many CMOS setups allow you to press a key (such as F10) to save values and exit all in one action.

Bad hardware

If after following all the above steps you continue to experience the same error when your computer starts or your computer is still unable to keep the stored values you are experiencing a more serious issues. Most likely causes are bad power supply or bad motherboard.