The document provides information about motherboard components and their functions, as well as how to troubleshoot motherboard failures. It discusses the main components of a motherboard including the back panel connectors, PCI slots, northbridge, southbridge, CPU socket, power connectors, and RAM slots. It then describes common motherboard failure symptoms and provides a multi-step process for troubleshooting, which involves checking for physical damage, voltages, and signals before attempting to replace failed components.

1. 1Motherboard components and their functions:
Motherboard is the heart of a computer system. It is called motherboard
because all features and peripherals plug to operate the whole systemare into it. Components
contained by motherboard are here below:
1. Back Panel Connectors & Ports:
Connectors and ports for connecting the computer to external devices such as display
ports, audio ports, USB ports, Ethernet ports etc.
2. PCI (Peripheral Component Interconnect) Slots:
Slot for older expansion cards such as sound cards, network cards, connector cards.
 PCI Express x1 Slots:
Slot for modern expansion cards such as sound cards, network cards (Wi-Fi,
Ethernet, Bluetooth etc.), and connector cards (USB) etc.
 PCI Express x16 Slot:
Slot for discrete graphic cards and high bandwidth devices
3. North Bridge:
It also known as Memory Controller Hub (MCH) .One of the most important
component of a motherboard.
Northbridge allows the CPU to communicate with the RAM and graphics card. It is responsible
for co-coordinating the data flow amongst the memory, video card and the processor.
4. Southbridge:
Also known as the Input/output Controller Hub (ICH).
It is responsible for coordinating the data flow between the processor and peripherals such as
sound cards and network cards.

2. 25. CPU Socket:
CPU insert here. The processor socket is the central piece of a motherboard, usually
being located near the center of the motherboard.
6. ATX 12V Power Connector: (processor power supply connector)
Connects to the 4 pin power cable of a power supply unit which supplies power to the
CPU.
7. ATX Power Connector: ( Motherboard power supply connector)
Connects to the 24-pin ATX power cable of a power supply unit which supplies power
to the motherboard.
8. Front Panel USB 2.0/3.0 Connector:
Connects to USB 2.0/3.0 ports at the front or top of the computer case.
9. Front Panel Connectors:
Connects to the power switch, reset switch, power LED, hard drive LED and front audio
ports of a computer case.
10. IDE and SATA ports:
IDE = Integrated Device Electronics
SATA = Serial ATA
IDE and SATA ports are used to provide connectivity for the storage devices and optical devices.
IDE was replaced by the smaller and much faster SATA interface.

3. 311. CMOS Battery ( Complementary Metal Oxide Semiconductor) :
It supplies power to store BIOS settings and keep the real time clock running.
The CMOS battery found on most motherboards is the lithium coin cell.
12. RAM/Memory Slots:
RAM insert here. The memory slots are used to house the computer’s memory
modules.
How to Troubleshootfor MotherboardFailures:
A computer motherboard is one of the hardest pieces of hardware to troubleshoot.
Failure symptoms:
 Every power on but you can’t see a live screen.
 Computer turns on for just a few seconds then turns off.
 Some peripherals work, others don’t.
 System shut off randomly.
Motherboard failures can be divided into three types:
1. Power failure
2. Bus failure
3. Component failure.
Due to the complexity in the structure and components in computer motherboards, the failure
rate is relatively high. Repair the failure using the following steps.
Steps 1:
Check that there is no sign of physical damage:
Determine whether the motherboard seems burned, blown, foam board, has
a broken connector, exploded capacitors or dirty fans and chips, etc.
Steps 2:
Check that BIOS battery provides sufficient voltage.

4. 4Steps 3:
Clean out the dust using a soft brush:
The failure may have been caused by dust. To keep the motherboard running
effectively for years, just make sure that the computer is clear of dust.
Steps 4:
Using a multimeter, measure the motherboard supply voltages. If there is an
abnormal voltage, check the power supply.
Steps 5:
Check the all chip clock, input and output signals. Until the faulty component
will be traced.
Steps 6:
Remove and replace the failed component(s) with the same type, then boot to
test operation.
Steps 7:
Use the tangent line by line method to find short circuit and trace the circuit
board to determine the failure source.
Steps 8:
If the above steps fail to fix the problem, find a motherboard with the same
characteristics and replace it completely.

5. 5
System bus-Functions &Features
The heart of any motherboard is the various buses that carry signals
between the components. It’s a pathway through which data can travel within a computer.
According To ASK.COM - A computer bus system is an electronic
pathway that the processor uses to communicate with the internal and external devices of a
computer system. Bus transfers data within the computer sub system and also sends
instructions and commands from the processor to various devices.
There are different types of bus systems such as data, address,
control etc. Here below the functions of some buses:
1) Data Bus:
Data bus is the most common type of bus. It is used to transfer data
between different components of computer. The number of lines in data bus affects the
speed of data transfer between different components. The data bus consists of 8, 16,
32, 64 lines. A 64-line data bus can transfer 64 bits of data at one time.
2) Address bus:
Many components are connected to one another through buses. Each
component is assigned a unique ID. This ID is called the address of that component. If a
component wants to communicate with another component, it uses address bus to
specify the address of that component. The address is a unidirectional bus. It can carry
information only in one direction. It carries address of memory location from
microprocessor to main memory.
3) Control Bus:
Control bus is used to transmit different commands or control signals from
one component to another component. A control signal contains the timing information
and command signal (type of operation to be performed)
4) Memory Bus:
The memory bus is used to transfer information between the CPU and the
main memory – RAM. This bus is connected to the North Bridge or Memory Controller
Hub chip.

6. 65) Processor Bus:
Also called the front side bus (FSB), this is the higher speed bus of the
system. This bus is used primarily by the processor to pass information to and from main
memory and the North Bridge. It is normally 64 bits wide.
6) AGP (Advanced Graphics Port) Bus:
This is a 32-bit bus specifically for a video card. It requires for very fast
performance of video on computers. It support high performance video like 3D graphics,
full-motion video etc. It runs at 66MHz, 133MHZ, 266MHz or 533MHz. It creates
connection between CPU and video card.
7) PCI (Peripheral Component Interconnect) Bus:
This is usually a 33MHz 32-bit bus found in virtually all systems. It connects
the CPU, memory and peripherals to wider and faster data pathway. High speed
peripherals such as network card, video card and more can be plugged into PCI Bus slot.
PCI-X and PCI-Express are faster developments of the PCI bus.
8) PCI-X:
PCI-X is a second generation development of the PCI Bus that provides faster
speeds than PCI. It is used primarily in workstation and server installations. PCI-X
supports 64-bit slots.
9) PCI-Express:
PCI-Express bus is a third generation development of the PCI bus. PCI-Express
is a differential signaling bus that can be generated by either the North Bridge or the
South Bridge. The speed of PCI-Express is described in terms of lanes.
10) ISA (Industry Standard Architecture) Bus:
This is an 8MHz 16-bit bus that supports older text-based applications. It is a
very slow speed bus, but it was ideal for certain slow-speed or older peripherals. It has
been used in the past for plug-in modems, sound cards and various other slow-speed
peripherals.
11) MCA (Micro Channel Architecture) Bus:
This bus was developed by IBM as an attempt to replace the ISA bus with
something ‘bigger’ and ‘better’. It is a 32-bit bus. It works on more speed in comparison
with ISA Bus.
12) USB (Universal Serial Bus):
This is an external bus standard that supports data transfer rates of 12
Mbps. A single USB port can be used to connect up to 127 peripheral devices including
mouse, modem, keyboard, printer, digital camera etc. USB has two versions- USB 1X and
USB 2X.

7. 7
Monitor
A monitor or a display is an electronic visual display for computers.
According to Harrod’s Librarians Glossary, “The device on which images generated by a PC, DVD
or video cassette recorder can be viewed”
The monitor comprises the display device, circuitry and an enclosure. The
display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-
LCD) thin panel, while older monitors used a cathode ray tube (CRT) about as deep as the
screen size.
The monitor is the piece of computer hardware that displays the video and
graphics information generated by the computer through the video card.
Monitors are very similar to televisions but usually display information at a
much higher resolution.
Monitor description
Monitors are display devices to the computer and connect via a cable to a port on the video
card or motherboard. Even though the monitor sits outside the main computer housing, it is an
essential part of the complete system.
Monitors come in two major types - LCD or CRT. CRT monitors look much like old-fashioned
televisions and are very deep in size. LCD monitors are much thinner, use less energy, and
provide a greater graphics quality.
LCD monitors have completely obsolete CRT monitors due to their higher quality, smaller
"footprint" on the desk, and decreasing price.
Monitors are built-in as part of the computer system in laptops, tablets, net books, and all-in-
one desktop machines.
Cathode Ray Tubes (CRTs):
The first computer monitors used cathode ray tubes (CRTs). Prior to the advent of home
computers in the late 1970s, it was common for a video display terminal (VDT) using a CRT
which was integrated with a keyboard and other components. The display was monochrome
and far less sharp and severely limited amount of information could be displayed at one time.

8. 8High-resolution CRT displays were developed for specialized military, industrial and scientific
applications but they were far too costly for general use.
The primary advantage that CRT monitors held over LCDs was their color rendering. The
contrast ratios and depths of colors displayed were much greater with CRT monitors than LCDs.
Many graphic designers still use the very expensive large CRT monitors in their work because of
the color advantages.
The other advantage that CRT monitors held over LCD screens is the ability to easily scale to
various resolutions. By adjusting the electron beam in the tube, the screen can easily be
adjusted downward to lower resolutions.
While these two items may play an important role for CRT monitors, there are disadvantages as
well. The biggest of these are the size and weight of the tubes. An equivalent sized LCD monitor
is upwards of 80% smaller in size and weight compared to a CRT tube. The other major
drawback deals with the power consumption. The energy needed for the electron beam means
that the monitors consumer and generate a lot more heat than the LCD monitors.
Advantages:
 Multisync Capable
 High Resolution
 Color Clarity and Depth
Disadvantages:
 Very Heavy and Large
 Use Large Amounts of Energy
 Generate Excess Heat
Liquid Crystal Display (LCDs):
A liquid crystal Display (LCD) is a flat panel display. These are used in wide range of applications
including computer monitors, televisions, instrument panel, aircraft cockpit display etc
The biggest advantage of LCD monitors is their size and weight. As was mentioned earlier, the
size and weight of an LCD monitor can be upwards of 80% lighter than an equivalent dimension
CRT screen. This makes it possible to users to have larger screens for their computers than was
possible before.
LCD screens also tend to produce less eye fatigue to the user.
The most notable disadvantage to LCD screens is their fixed resolution. An LCD screen can only
display the number of pixels in its matrix and no more or less.

9. 9Advantages:
 Smaller and Lighter
 Energy Efficient
 Causes Less Eye Fatigue
Disadvantages
 Blurry Images Outside Native Resolution
 Motion Blur on Fast Moving Images
 Some Models Have Reduced Color Clarit
CRT vs LED
Parameters CRT LCD
1. Stands For CRT stands for “Cathode Ray Tube“. LCD stands for “Liquid
Crystal Display“.
2. Size CRT is large in size. LCD is thin in size.
3. Weight Heavy Light
4. Cost It is less expensive. It is more expensive.
5. Thickness Bulky due to the heavy back Pretty slim
6. Brightness High Low
7. Colors 8-bit max, 16.7 million colors. 32 bit
8. Power
Consumption
It consumes High power. It consumes Low power.
9. Heat
generation
Because of high speed, CRT generates
more heat.
Because of low speed, LCD
generates heat less than
CRT.
10. Contrast ratio High contrast ratio. Very poor contrast ratio.
11. Resolution
flexibility
High quality can display natively in
almost any resolution.
Late-model LCD panels offer
greater quality when used at
non-native resolutions.
12. Image Quality Sharper images Slightly less sharp images

10. 1013. Automatic
Readjustment
The Auto-fit does not properly readjusts
the image
Auto resize button;
readjusts the pixels
14. Dead / Stuck
Pixel
Doesn’t happen as images are “painted” May happen
15. Radiation Has a significant amount of radiation Small amount of radiation
16. Glare Glare is reduced by the use of special
filters and treated glass.
Little or no glare
17. Viewing Angle Wide viewing angle Depends on the technology
18. Display
Sharpness
Slightly less sharp images Sharp
19. Blackness True black Blackness varies from dark
gray to gray
20. Video Ideal for any video including HD Not ideal for Standard
Definition videos, but great
for High Definition videos
21. Warmness Back gets noticeably warm after some
time
Little
22. Burn-In Suffers from burn-in problem. LCDs are free from the burn-
in issue that plagues CRTs
and Plasma displays.
23. Response
time
CRT having fast response. LCD having slow response.
24. Problems CRT monitors constitute a hazard .It can
cause headaches in migraine sufferers.
There is no such problem in
LCD screen.
25. Portability Because of large size it is not easy to
portable.
Easily portable
26. Where used CRT is used in Televisions and was used
in old computer monitors.
LCD is used in flat screens.
Troubleshoot Monitor
Troubleshooting is a form of problem solving. It is a process of identifying the source of
problem and to fix it. A PC monitor may face different number of problems. Following steps
may be followed to get rid of it.

11. 111. Check to make sure that the power is correctly on. If the input voltage for the power
supply is not correct then computer may not turn on completely. Some monitors have
more than one power button or switch - check to make sure that all switched on.
2. There is a 15volt connector with the monitor. Make sure that the connector is plugged
correctly.
3. Contrast and brightness are another reasons for trouble occurrence. Turn up the
monitor's brightness and contrast settings completely.
4. Problem may occur for reason of hardware problem. Make sure that each and every
hardware component worked properly.
5. If a monitor being turn on for several minutes then it goes to the sleeping mood. To
awake the monitor just fluctuate the mouse.
6. Test the monitor to another PC.
7. Finally, if all else fails, then it requires the computer manufacturer's technical support.
8. If the problem doesn’t fix yet in above methods then no way but replace the monitor.
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