Monitors Chapter 14 Release 22/10/2010powered by dj.

Monitors

Chapter 14

Release 22/10/2010 powered by dj

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Objectives - I

Identify the different types of monitors List the features of the monitor Explain monitor settings Install the monitor Test the monitor List the features of the video adapter


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Objectives - II

List the components of the video adapter List the video adapter standards Install the video adapter Troubleshoot the monitor Troubleshoot the video adapter


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Types of Monitors

Output device that displays information

Types of monitors

Cathode Ray Tube Monitor Liquid Crystal Display TFT Monitors


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Working of CRT Monitor - I

In CRT technology, the filaments at the back of the cathode tube shoot a beam of electrons to the screen at front of the tube.

Plates on the top, bottom, and sides of the tube control the direction of the beam.

The beam of is directed by these plates to start at the top of the screen, move from left to right to make one line, and then move down to the next line, again moving from left to right.

As the beam moves vertically down the screen, it builds the image.


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Working of CRT Monitor - II

By turning the beam on and off and selecting the correct color combination, the grid in front of the filaments controls what goes on the screen when the beam hits that portion of the line or a single dot on the screen.

When hit, special phosphors on the back of the monitor screen light up and produce colors.

The grid controls which one of three electron guns fires, each gun targeting a different color (red, green, or blue) positioned on the back of the screen


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Question for GD Time Limit – 3 Mins

How does a CRT monitor work?


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Cathode Ray Tube Monitor (CRT)

Displays images with colors that are consistent and can be viewed comfortably from different angles

Types of CRT

Monochrome Monitor Grayscale Monitor Color Monitor


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Types of CRT Monitor - I

Monochrome Monitor - Displays the image on the screen using only one color such as green, orange or white on a background of a contrast color such as black or white.

Gray Scale Monitor - Displays the image on the screen using different shades of gray. Can display both text and graphics like a black and white television


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Types of CRT Monitor - II

Color Monitor - Are useful to display colorful graphics and animations. Displays images using the three colors red, blue, and green. Mixes these three colors in different combinations to display a variety of colors


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Liquid Crystal Display Monitor

Thin and use little space Picture on the LCD monitor does not

flicker and thus reduces eyestrain as the whole image is drawn at once on the LCD screen

Used in laptops, microwave ovens


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Working of LCD Monitor - I

An LCD monitor produces an image using a liquid crystal material made of large, easily polarized molecules.

At the center of the layers is the liquid crystal material.

Next to it is the layer responsible for providing color to the image.

These two layers are sandwiched between two grids of electrodes.

One grid of electrodes is aligned in rows.


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Working of LCD Monitor - II

The two layers of electrodes make up the electrode matrix.

Each intersection of a row electrode and column electrodes forms one pixel on the LCD panel.

Software can manipulate each pixel by activating the electrodes that form it.

The image is formed by scanning the column and row electrodes, much as electronic beam scan a CRT monitor screen


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What are the different layers available in a LCD monitor?


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TFT Monitors

Uses Thin-Film Transistor technology Tiny transistor is used for each pixel on the

display Allows faster re-drawing of the image Displays sharp text, excellent color and an

improved response time for multimedia applications. Viewing angles are often in a range of +-30 to +-70 degrees

Has a sandwich-like structure with liquid crystal filled between two glass plates

TFTs are actually the number of pixels displayed


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Working of TFT Monitor - I

Using TFT technology, a transistor that amplifies the signal is placed at every intersection in the grid, which further enhances the pixel quality

Sometime called active matrix display.


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Working of TFT Monitor - II


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Plasma Monitor - I

Plasma technology contains a Plasma Display Panel (PDP), which is commonly used for large size displays.


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Plasma Monitor - II


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Working of Plasma Monitor - I

Plasma monitor is flat display device. Has thousands of tiny cells, which contains

xenon and neon gas placed between two glass plates.

Electrodes are also sandwiched between two flat glass plates.

Electrodes used in the plasma monitor are transparent display electrodes and address electrodes.


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Working of Plasma Monitor - I

The transparent display electrodes are placed in front of the cells along the front glass plate and the address electrodes are placed behind the cells.

The transparent display electrodes are surrounded by an insulating dielectric material and covered by a magnesium oxide protective layer.

The glass panels are vacuum sealed.


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What is the difference between LCD and TFT monitor?


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Difference between LCD and Plasma


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LED Monitor

LED computer monitor has been mainly appreciated for its low power consumption and its great performance which has been considered as perfect for office type of productivity.

Uses LEDs to illuminate the display. Samsung and LG are manufacturing LED Monitor in

market. Uses LED backlight replacing the standard cold

cathode fluorescent lamps which was used in LCD monitor.


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Features of the Monitor

Size – Specifies the length of the monitor in inches and measured diagonally. Available in different sizes ranging from 14 inches to 22 inches

Resolution – Specifies the number of pixels. More the dots, the higher the resolution, the more sharp and clear image will be displayed on the screen

Contrast Ratio - Contrast Ratio is the comparison to the whitest white color to the darkest black a set can produce.


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List the different features of a monitor.


Sl. Features of a Monitor

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Monitor Settings - I

Brightness – Changes the amount of light in an image. Enables you to brighten the display picture on the screen when it appears dark and vice versa

Contrast – Specifies the difference between the lighter and the darker colors. Higher the contrast, the more is the difference between the two contrasting colors

Horizontal Size – Increases and decreases the size of the horizontally displayed image

Vertical Size – Increases and decreases the size of the vertically displayed image


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Ask the students how to adjust brightness and contrast setting of the monitor.


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Monitor Settings - II

Horizontal position – Moves the displayed image to the right and left directions on the screen

Vertical position – Moves the displayed image up and down on the screen

Degauss – Removes the magnetism from the monitor and restores the displayed picture

Language – Enables to modify the setting name and description on the screen

Corner/Trapezoid correction – Corrects the distortion in the displayed image


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What is the use of degauss button?


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Practical

Perform the activity mentioned in Lab no. 1 in the text book:

• To install the monitor stand.


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Practical


• To use the POST to check if the monitor is working.


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Video Adapters Display both 2-Dimensional and 3-

Dimensional images Working of the Video Adapters


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How does a video adapter work?


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Components of Video Adapter - I


Video Processor

Video RAM

Video BIOS

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Components of Video Adapter - II

Video BIOS - A ROM chip that is built on the video adapter. Enables communication between the system and Video processor, as it understands the language of both the system and Video processor

GPU - Graphics Processing Unit is like the CPU which is used primarily for computing 3D functions. This includes things such as lighting effects, object transformations, and 3D motion. Clock rate of GPU ranges from 250 MHz to 850 MHz.


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Components of Video Adapter - III

Video RAM (VRAM) - A memory that the video adapter uses to hold the image displayed on the monitor screen and frees up the system memory, which would otherwise hold the image displayed on the monitor screen

RAMDAC - Converts digital signals from the system to analog signals and sends them to the monitor


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Types of Video RAM - I

Video RAM - VRAM was used on video cards for awhile. It was more expensive than EDO, but the performance increase was noticeable.

Synchronous Graphics RAM - SGRAM and SDRAM are used on many modern cards today where speed is an issue. SGRAM is clock-synchronized, like SDRAM used for main system memory.


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Types of Video RAM - II

Window RAM – WRAM is modified VRAM. It boasted slightly better performance than VRAM and cost less to make. For this reason, it was often used in place of VRAM on many video cards.

Double Data Rate (DDR) - It is the type of memory used mostly today.

The memory capacity of most modern video cards range from 128 MB to 4.0 GB. The memory clock rates in modern cards are generally between 400 MHz and 3.8 GHz


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List the different components of a Video Adapter.


Sl. Components of Video Adapter

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Types of Connectors - I

Video Graphics Array (VGA) (DB-15) - Analog-based standard adopted in the late 1980s designed for CRT displays, also called VGA connector. Some problems of this standard are electrical noise, and image distortion etc.

S-Video - Video In Video Out (VIVO) for S-Video, Composite video and Component video included to allow the connection with televisions, DVD players, video recorders and video game consoles.


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Types of Connectors - II

Digital Visual Interface (DVI) - Digital-based standard designed for displays such as flat-panel displays (LCDs, plasma screens, wide High-definition television displays) and video projectors.

It avoids image distortion and electrical noise, corresponding each pixel from the computer to a display pixel, using its native resolution.


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VGA Connector Wiring

Pin No. 1 – Red Pin No. 2 – Green Pin No. 3 – Blue Pin No. 6 – Red Ground Pin No. 7 – Green Ground Pin No. 8 – Blue Ground Pin No. 13 – H Sync Pin No. 14 – V Sync


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Standards of Video Adapter

Standard Resolution

Video Graphics Array (VGA) 640 x 480

Super VGA (SVGA) 800 x 600

Extended Graphics Array (XGA) 1024 x 768

Super XGA (SXGA) 1280 x 1024

Ultra XGA (UXGA) 1600 x 1200


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Ask the students to draw the image of a SVGA connector with pin description?


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PCI Display Card

A circuit board that plugs into the computer’s PCI bus.

The PCI bus will enhance the speed of the transfers from 33MHz to 133 MHz with a transfer rate of 1 GB/s.


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PCIe Display Card

Cheaper than PCI or AGP to implement on board levels.

Has point-to-point connection (it does not share bandwidth but communicates directly with devices through switch).


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AGP Display Card

AGP is a channel for attaching a video card to the motherboard, primarily to help in 3D computer graphics.

Advantage of AGP over PCI is that it has a dedicated pathway between slots and processor rather than sharing PCI bus.


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Sl. Types of Display Card


List the different types of display card.

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TV Tuner Card

Used to record television programs onto the hard disk.

Available as PCI bus expansion card, PCIE bus or USB devices.

The card contains a tuner, receiver, demodulator and analog to digital converter.


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Video Capture Card

Stores the digital video on a computer’s storage device.

Plugged into the expansion slots like PCI, PCIE or AGP in PCs.

Different manufacturers are ATI, Canopus, Matrox, and Pinnacle Systems.


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Projector

Used for projecting a beam of light or a machine for projecting an image onto screen.

A computer projector works by transferring a signal through a VGA cable from the computer to the projector in order to display the image output onto a screen. The different types of projector are:• Desktop Projector

• Home Theatre Projector


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Practical


• To install the graphics card in a PC.


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Components inside a CRT Monitor - I

Primary Power SupplySecondary Power SupplySystem ICSync ICVertical ICHorizontal YokeVertical yoke


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Components inside a CRT Monitor - II

EHT (I/P – 100V DC and O/P – 25000V AC)Color Input ICSignal/Inverter ICHorizontal ICAmplifier Transformer (IRF)sMemory ICPower Supply IC


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Components inside a LCD/TFT Monitor - I

Power SupplyLogic BoardInverter Board (I/P – 12V DC and O/P is

2kV AC or 12V DC)LCD panel – consist LCD panel board and

tube


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Components inside a LCD/TFT Monitor - I

Logic Board consists of components mentioned below: • Power regulator IC• Main IC• Display IC• AGP IC• BIOS


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Troubleshooting Monitor - I

Different types of problems that may occur are:• Color patches• Screen size is bigger but picture is smaller• Picture comes on with low contrast and later it

comes properly• Display Picture Appears Wavy or have color

patches


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Troubleshooting Monitor - II

• Display is a little Fuzzy• Monitor generates humming sound• Monitor Shows Curvy or Wavy Lines• Computer boots but Monitor Is Blank• Monitor Screen displays a bluish/greenish color• Monitor Flickering


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Problems related to TFT/LCD monitor

Zebra lines or plain raster• Change LCD board or tube

• Display shows lightly or very lightly

• Check defective tube

• Check inverter board by replacing with a new one

Intermittent Display• Check for dry soldering

• Check logic board by checking the input and output voltages.

• Check BIOS IC by pressing it or reprogram the BIOS.


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Replacing the monitor cable

Monitor cable has two end in which one end is plugged inside the monitor and the other end has a D-15 pin and is connected to the system. The end which is plugged inside the monitor is damaged very rarely. But if the cable gets damaged then the full cable has to be replaced along with the D-15 pin.


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Practical


• To replace the monitor cable.


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Troubleshooting the video adapter

It is preferred to troubleshoot the monitor before troubleshooting the video adapter.

Open the system and push the video adapter firmly into the expansion slot if it is loose.

Remove the video adapter from the current expansion slot and install it in another free expansion slot. Clean the slot before installing the video adapter.

Replace the mother board, if the video adapter is integrated (in-built) with the mother board.


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Most Common Problems - I

Problem Cause Solution Periodic changes in color, brightness, size, or position

Loose connections inside the monitor or the cable connecting the video adapter.

Check the video adapter connections

Ghosts, shadows, or streaks adjacent to vertical edges in the picture

Occurs with cable extensions, excessively long cables, cheap or low standard video cables

Check the cable connections.

Electromagnetic Interference (EMI)

Nearby equipment like monitors or power lines

Locate and place the sources of magnetic fields away from CRT. Degauss the CRT


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Most Common Problems - IIProblem Cause Solution Wiring transmitted interference

Noisy AC power occurs due to other equipment using electric motors e.g., vacuum cleaners, lamp dimmers or motor speed controls, fluorescent lamps, and other high power devices, may result in a variety of effects

Plugging the monitor into another outlet or the use of a line filter may help. If possible, replace or repair the offending device

Monitor not locking on one or more video scan ranges

Fault in the video source or monitor dealing with the sync signals

Correct the settings of video adapter.


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Most Common Problems -III

Problem Cause Solution Adjustments needed for background brightness or focus

Aging CRT reduces brightness

Needs adjustments through the menus that are provided on the monitor panel

Dead monitor due to power supply problems

Bad connections, blown fuse or other component

Change the blown fuse, Check component if damaged.


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Summary - I

The monitor is an output device. Monochrome monitors displays images on the screen

using only one color. Gray-scale monitors display images on the screen

using different shades of gray. Color monitors display images in a variety of colors. CRT monitor is an economical monitor used in most

systems. LCD monitors are thin and they use little space.


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Summary - II Monitors can have a portrait or a landscape orientation. Pixels are the tiny dots that make up an image on the

monitor. The resolution specifies the number of pixels that the

monitor screen can display. The monitor settings enable you to adjust the monitor

display settings. You can install the monitor by connecting it to the

system.


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Summary - III

The video adapter sends the images from the system to the monitor.

The video adapter has the Video BIOS, GPU, Video RAM, and RAMDAC.

The video adapter standards specify the resolution and the colors that the video adapter uses to draw the display image to the monitor.

The video adapter is installed on the system motherboard.


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Explorative Work

MonitorSl. Make Size Type Contrast Ratio Resolution Support Interface Approx. Cost1 2 3 4 5


Display Adapter Card

Sl. Make Type VRAM Type/Capacity Interface Resolution Support Approx. Cost

1

2

3

4

5

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Mind Map

Draw a mind map to summarize this chapter


Monitors Chapter 14 Release 22/10/2010powered by dj.

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