The motherboard is a big circuit board inside your computer. The motherboard contains the connectors for attaching devices to your computer. These devices can range from a mouse to a modem to memory.

 The motherboard acts as the central nervous system for a computer, transmitting information back and forth between the brain of the computer (CPU) and various parts (components and peripherals). Every individual piece of a computer connects to the motherboard in one way or another.  

 A motherboard can also be called a main board, a system board or a planar boards.

 “Think of a motherboard as a scale model of a futuristic city with many modular plug-in buildings, each using power from a common electrical system. Multiple-lane highways of various widths transport data between the buildings. The motherboard is the data and power infrastructure for the entire computer.” (Taken from www.howthingswork.com)

A motherboard is a multi-layered printed circuit board. Copper circuit paths called traces that resemble a complicated roadmap carry signals and voltages across the motherboard.

A motherboard has many different slots, chips and pins on it. Let’s discuss what some of the more common ones are.

There are many different form factors (styles) of motherboards. The main form factor in use today is the ATX form factor motherboard. Depending on the form factor of a motherboard you may have different capabilities or different types of connectors.

Motherboard

 The Processor Slot/Socket

 This is where the processor sits in the computer. It plugs into the motherboard. We will discuss the function of the processor more in depth later. There are two types of processor connections found on motherboards. They will be slotted or socketted .This means that the type of connector on the motherboard must match the type of processor that you put in. There are also different types of socketted and slotted processor slots. The amount of connectors or pin slots varies between types.

 Socketted Processor Connector                        Slotted Processor Connector

 RAM Slots

These are also slots on the motherboard. These are used to connect memory to the motherboard. These slots will usually be black in color and have some form of push tabs on the end for releasing the memory module that have been inserted. The numbers of memory slots on a motherboard vary depending on the type of motherboard. There is never just one memory slot on a motherboard and the memory slots always run parallel to each other.

Ram Slots

 IDE Connectors

These are the connectors for any IDE devices that you put into your computer. Common IDE devices are Hard Drives and CD-ROM drives. There are two of these IDE connectors on a motherboard. They are called the Primary IDE Connector (for main devices) and the Secondary IDE Connector (for secondary, less important devices). If you look very closely on the motherboard you will find tiny labels for each of these connectors so that you know which one is the primary and which one is the secondary. You plug the IDE cables for your IDE hardware into these connectors.

Today these slots are ‘keyed’. When you plug an IDE cable into a connector there is a certain way that it should be plugged in. Keyed means that there is a way to tell which way to do this. There are two mains methods of keying a connector or it’s cable. The first is to put a lip on the cable that plugs into an opening on the side of the connector (figure 3) and the second way is to fill in a spot where a pin would usually be. (figure 4). Keying helps to make sure that your cables are plugged in properly and that the devices they connect to function. If there is no keying method used for the connector and the cable there is always one last way to find out.

 Floppy Connector

There is one floppy connector on most motherboards. The floppy connector will be near the IDE connectors on most motherboards and is a bit shorter than an IDE connector. You plug the floppy cable that comes from your floppy drive into this connector so that it can be used by the computer.

 CMOS Battery

 The CMOS battery looks like a big watch battery. It is 3 volts. The job of the CMOS battery is to supply enough power to your computer that when it is turned off it can still store low level information for your computer. An example of this information is the date and time on your computer. Each time you turn your computer on the date and time is correct, even if the computer has been off for a couple days. These batteries do not last forever and if you notice that you start to lose time on your computer it is time to replace the CMOS battery.

 BIOS Chip 

 BIOS stands for Basic Input Output System. The BIOS is built-in software that determines what a computer can and cannot do. The BIOS contains all the code required to control hardware devices in your computer. The BIOS chips is the physical location where the BIOS setup program is stored. This allows the BIOS to still function even if other hardware components may not. We will discuss the BIOS more in depth later.

 ISA

 ISA is a connector or bus for ISA type expansion cards. A bus is the channel or path between the components in a computer. There are many types of buses. ISA is just one of them. ISA connectors are an older type of bus. Most current motherboards will no longer have ISA slots on them. ISA slots are usually black in color, appear along the bottom of the motherboard and are the longest of expansion slots on the motherboard.

 PCI

 PCI is a newer bus and the most current for the majority of expansion cards. Most motherboards have multiple (from 3 – 6) PCI slots on them. PCI slots are usually beige in color and appear above the ISA slots on a motherboard or if there are no ISA slots, along the bottom of the motherboard. PCI and ISA buses connect to the motherboard through a bridge.

 AGP

 Accelerated Graphics Port. This is the newest type expansion card connector on motherboards today. This connector is used for dedicated video and can only support AGP video cards. AGP supports faster performance and direct access to system memory.

 Power Connector

 The power connector on the motherboard is used to plug the power supply into the motherboard in order to provide power for expansion cards, memory and processors. The power connector is a 20 pin connector.

Motherboard Specifications

 Motherboards have various different specifications. Some specifications you might hear are;  

• Number of slots and what type

• Number of I/O connectors and what type

• Supported memory and processor

• Bus speeds

Motherboard Problems

 Some problems that you may experience with motherboards are non-functional expansion slots, processor sockets, IDE connectors and memory sockets. When these areas of a motherboard become non-functional the devices hooked to or plugged into them will no longer work.

There are also problems when buses or chipsets on the motherboard stop working. These problems will usually render parts or all of your motherboard non-functional.

Some motherboards require jumper settings. Jumpers are small plastic covers that fit onto pins on the motherboard. Based on how these jumpers are put on, different settings can be achieved. Incorrect jumper settings can cause a motherboard to stop working temporarily or permanently.

Motherboard Troubleshooting

 Motherboards are usually the last device to be suspected of causing any hardware problems. Most troubleshooting will start with the problem device.

 Some motherboards may emit a series of beeps, called a beep code. This code can be researched on the Internet to find out what the issue may be. Motherboards may also have a small light on them called an LED. The color of this LED can also be used to determine where an issue lies. These LED codes can be researched on the Internet using the manufacturers’ website.

Knowledge Check #2

Match the components on the left to their description on the right.

Please include your answer to this question in the email that you started previously.

Click on the blue arrow to continue

Return to Table of Contents