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Unformatted text preview: All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 19 C HAPTER Video
In this chapter, you will learn how to
• Explain how video displays work
• Select the proper video card
• Install and configure video
• Troubleshoot basic video problems The term video encompasses a complex interaction among numerous parts of the PC,
all designed to put a picture on the screen. The monitor or video display shows you what’s
going on with your programs and operating system. It’s the primary output device for
the PC. The video card or display adapter handles all of the communication between the
CPU and the monitor (see Figure 19-1). The operating system needs to know how to
handle communication between the CPU and the display adapter, which requires drivers specific for each card and proper setup within Windows. Finally, each application
needs to be able to interact with the rest of the video system. Figure 19-1
and video card Let’s look at monitors and video cards individually. I’ll bring them back together as a
team later in the chapter so you can understand the many nuances that make video so
challenging. Let’s begin with the video display and then move to the video card. 817 ch19.indd 817 12/9/09 5:13:31 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 818 Video Displays
To understand displays, you need a good grasp of each component and how they work
together to make a beautiful (or not so beautiful) picture on the screen. Different types
of displays use different methods and technologies to accomplish this task. Video displays for PCs come in three varieties: CRT, LCD, and projectors. The first two you’ll see
on the desktop or laptop; the last you’ll find in boardrooms and classrooms, splashing
a picture onto a screen. Historical/Conceptual
Cathode ray tube (CRT) monitors were the original computer monitors—those heavy,
boxy monitors that take up half your desk. Although for the most part they’ve been
replaced by LCD technology on new systems, plenty of CRT monitors are still chugging
away in the field. As the name implies, this type of display contains a large cathode
ray tube, a type of airtight vacuum tube. One end of this tube is a slender cylinder that
contains three electron guns. The other end of the tube, which is fatter and wider, is the
Before we begin in earnest, I want to give you a note of warning about the inside of a
traditional monitor. I will discuss what can be repaired and what requires more specialized expertise. Make no mistake—the interior of a monitor might appear similar to the
interior of a PC because of the printed circuit boards and related components, but the similarity ends there. No PC has voltages exceeding 15,000 to 30,000 V, but most monitors
do. So let’s get one thing perfectly clear: Opening up a monitor can kill you! Even when
the power is disconnected, certain components retain a substantial voltage for an extended
period of time. You can inadvertently short one of the components and fry yourself—to
death. Given this risk, certain aspects of monitor repair lie outside the necessary skill set for
a normal PC support person, and definitely outside the CompTIA A+ certification exam
domains! I will show you how to address the problems you can fix safely and make sure
you understand the ones you need to hand over to a monitor shop.
CAUTION The inside of a CRT has very high voltage components. These can,
literally, kill you. Be careful!
The inside of the display screen has a phosphor coating. When power is applied to
one or more of the electron guns, a stream of electrons shoots towards the display end
of the CRT (see Figure 19-2). Along the way, this stream is subjected to magnetic fields
generated by a ring of electromagnets called a yoke that controls the electron beam’s
point of impact. When the phosphor coating is struck by the electron beam, it releases
its energy as visible light.
When struck by a stream of electrons, a phosphor quickly releases a burst of energy. This happens far too quickly for the human eye and brain connection to register. ch19.indd 818 12/9/09 5:13:31 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 819 Figure 19-2
in the CRT Fortunately, the phosphors on the display screen have a quality called persistence, which
means the phosphors continue to glow after being struck by the electron beam. Too
much persistence and the image is smeary; too little and the image appears to flicker.
The perfect combination of beam and persistence creates the illusion of a solid picture. Essentials
The monitor displays video data as the electron guns make a series of horizontal sweeps
across the screen, energizing the appropriate areas of the phosphorous coating. The
sweeps start at the upper-left corner of the monitor and move across and down to the
lower-right corner. The screen is “painted” only in one direction; then the electron
guns turn and retrace their path across the screen, to be ready for the next sweep. These
sweeps are called raster lines (see Figure 19-3).
sweep from left
to right. ch19.indd 819 12/9/09 5:13:34 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 820 The speed at which the electron beam moves across the screen is known as the horizontal refresh rate (HRR), as shown in Figure 19-4. The monitor draws a number of lines
across the screen, eventually covering the screen with glowing phosphors. The number
of lines is not fixed, unlike television screens, which have a set number of lines. After
the guns reach the lower-right corner of the screen, they turn off and point back to the
upper-left corner. The amount of time it takes to draw the entire screen and get the electron guns back to the upper-left corner is called the vertical refresh rate (VRR), shown in
refresh rate Figure 19-5
refresh rate The monitor does not determine the HRR or VRR; the video card “pushes” the monitor at a certain VRR and then the monitor sets the corresponding HRR. If the video
card is set to push at too low a VRR, the monitor produces a noticeable flicker, causing
eyestrain and headaches for users. Pushing the monitor at too high a VRR, however,
causes a definite distortion of the screen image and will damage the circuitry of the
monitor and eventually destroy it. The number one killer of monitors is improper VRR
settings, and the number one reason your office is filled with crabby workers is that the ch19.indd 820 12/9/09 5:13:36 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 821 VRR is set too low. All good PC support techs understand this and take substantial time
tweaking the VRR to ensure that the video card pushes the monitor at the highest VRR
without damaging the monitor—this is the Holy Grail of monitor support! Phosphors and Shadow Mask
All CRT monitors contain dots of phosphorous or some other light-sensitive compound
that glows red, green, or blue (RGB) when an electron gun sweeps over it. These phosphors
are evenly distributed across the front of the monitor (see Figure 19-6). Figure 19-6
A monitor is a
grid of red, green,
and blue phosphors. A normal CRT has three electron guns: one for the red phosphors, one for the blue
phosphors, and one for the green phosphors. It is important to understand that the
electron guns do not fire colored light; they simply fire electrons at different intensities,
which then make the phosphors glow. The higher the intensity of the electron stream,
the brighter the color produced by the glowing phosphor.
Directly behind the phosphors in a CRT is the shadow mask, a screen that allows only
the proper electron gun to light the proper phosphors (see Figure 19-7). This prevents,
for example, the red electron beam from “bleeding over” and lighting neighboring blue
and green dots.
Shadow mask ch19.indd 821 12/9/09 5:13:41 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 822 The electron guns sweep across the phosphors as a group, turning rapidly on and off
as they move across the screen. When the group reaches the end of the screen, it moves
to the next line. It is crucial to understand that turning the guns on and off, combined
with moving the guns to new lines, creates a mosaic that is the image you see on the
screen. The number of times the guns turn on and off, combined with the number of
lines drawn on the screen, determines the number of mosaic pieces used to create the
image. These individual pieces are called pixels, from the term picture elements. You can’t
hold a pixel in your hand; it’s just the area of phosphors lit at one instant when the
group of guns is turned on. The size of pixels can change, depending on the number of
times the group of guns is turned on and off and the number of lines drawn.
NOTE Not all CRT monitors use dots. The Sony Trinitron line of CRT
monitors uses bars of red, green, and blue instead of dots. The holes in the
shadow mask have a rectangular shape. Many people feel this makes the
monitor’s image much crisper and clearer. Somebody must agree with them
because the Trinitron enjoys tremendous popularity. Even though the phosphors and
shadow mask have a different shape, everything you learn here applies to Trinitrons also. Resolution
Monitor resolution is always shown as the number of horizontal pixels times the number of vertical pixels. A resolution of 640 × 480, therefore, indicates a horizontal resolution of 640 pixels and a vertical resolution of 480 pixels. If you multiply the values
together, you can see how many pixels are on each screen: 640 × 480 = 307,200 pixels
per screen. An example of resolution affecting the pixel size is shown in Figure 19-8.
Some common resolutions are 640 × 480, 800 × 600, 1024 × 768, 1280 × 960, 1280 ×
1024, and 1600 × 1200. Notice that most of these resolutions match a 4:3 ratio. This
is called the aspect ratio. Many monitors are shaped like television screens, with a 4:3
aspect ratio, so most resolutions are designed to match—or at least be close to—that Figure 19-8
pixel size ch19.indd 822 12/9/09 5:13:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 823 shape. Other monitors, generically called wide-screen monitors, have a 16:9 or 16:10 ratio. Two of the common resolutions you’ll see with these monitors are 1366 × 768 and
1920 × 1200.
NOTE See the “Video Modes” section later in this chapter for the names of
The last important issue is to determine the maximum possible resolution for a
monitor. In other words, how small can one pixel be? Well, the answer lies in the phosphors. A pixel must be made up of at least one red, one green, and one blue phosphor
to make any color, so the smallest theoretical pixel would consist of one group of red,
green, and blue phosphors: a triad (see Figure 19-9). Various limitations in screens,
controlling electronics, and electron gun technology make the maximum resolution
much bigger than one triad. Figure 19-9
One triad Dot Pitch
The resolution of a monitor is defined by the maximum amount of detail the monitor
can render. The dot pitch of the monitor ultimately limits this resolution. The dot pitch
defines the diagonal distance between phosphorous dots of the same color, and is measured in millimeters (mm). Because a lower dot pitch means more dots on the screen,
it usually produces a sharper, more defined image (see Figure 19-10). Dot pitch works
in tandem with the maximum number of lines the monitor can support to determine
the greatest working resolution of the monitor. It might be possible to place an image
at 1600 × 1200 on a 15-inch monitor with a dot pitch of 0.31 mm, but it would not be
The dot pitch can range from as high as 0.39 mm to as low as 0.18 mm. For most
Windows-based applications on a 17-inch monitor, many people find that 0.28 mm is
the maximum usable dot pitch that still produces a clear picture. ch19.indd 823 12/9/09 5:13:54 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 824 Figure 19-10
Bandwidth defines the maximum number of times the electron gun can be turned on
and off per second. Bandwidth is measured in megahertz (MHz). In essence, bandwidth
tells us how fast the monitor can put an image on the screen. A typical value for a
better-quality 17-inch color monitor would be around 150 MHz, which means that the
electron beam can be turned on and off 150 million times per second. The value for a
monitor’s bandwidth determines the maximum VRR the video card should push the
monitor for any given resolution. It reads as follows:
maximum VRR = bandwidth ÷ pixels per page
For example, what is the maximum VRR that a 17-inch monitor with a bandwidth of
100 MHz and a resolution of 1024 × 768 can support? The answer is
maximum VRR = 100,000,000 ÷ (1024 × 768) = 127 Hz
That’s a pretty good monitor, as most video cards do not push beyond 120 Hz! At a
resolution of 1200 × 1024, the vertical refresh would be
100,000,000 ÷ (1200 × 1024) = 81 Hz
So, we would make sure to set the video card’s VRR to 80 Hz or less. If you had a
monitor with a bandwidth of only 75 MHz, the maximum VRR at a 1200 × 1024 resolution would be only 61 Hz.
Most monitor makers know that people aren’t going to take the time to do these
calculations. Instead, they do the calculations for you and create tables of refresh rates
at certain resolutions to show what a monitor can do.
Great! Now that you have the basics of CRT monitors, let’s turn to LCD monitors.
Although the technology differs dramatically between the monitor types, most of the
terms used for CRTs also apply to LCD functions. LCD Monitors
Liquid crystal displays (LCDs) are the most common type of display technology for PCs.
LCD monitors have many advantages over CRTs. They are thinner and lighter, use
much less power, are virtually flicker free, and don’t emit potentially harmful radiation. ch19.indd 824 12/9/09 5:13:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 825 LCDs still have resolution, refresh rates, and bandwidth, but LCDs also come with their
own family of abbreviations, jargon, and terms you need to understand so you can
install, maintain, and support LCDs. How LCDs Work
The secret to understanding LCD panels is to understand the concept of the polarity of
light. Anyone who played with a prism in sixth grade or has looked at a rainbow knows
that light travels in waves (no quantum mechanics here, please!), and the wavelength
of the light determines the color. What you might not appreciate is the fact that light
waves emanate from a light source in three dimensions. It’s impossible to draw a clear
diagram of three-dimensional waves, so instead, let’s use an analogy. To visualize this,
think of light emanating from a flashlight. Now think of the light emanating from that
flashlight as though someone was shaking a jump rope. This is not a rhythmic shaking,
back and forth or up and down; it’s more as if a person went crazy and was shaking the
jump rope all over the place—up, down, left, right—constantly changing the speed.
That’s how light really acts. Well, I guess we could take the analogy one step further
by saying the person has an infinite number of arms, each holding a jump rope shooting
out in every direction to show the three- dimensionality of light waves, but (a) I can’t draw
that and (b) one jump rope will suffice to explain LCD panels. The varying speeds create wavelengths, from very short to very long. When light comes into your eyes at many
different wavelengths, you see white light. If the light came in only one wavelength, you
would see only that color. Light flowing through a polarized filter (like sunglasses) is
like putting a picket fence between you and the people shaking the ropes. You see all
of the wavelengths, but only the waves of similar orientation. You would still see all of
the colors, just fewer of them because you only see the waves of the same orientation,
making the image darker. That’s why many sunglasses use polarizing filters.
Now, what would happen if you added another picket fence but put the slats in a
horizontal direction? This would effectively cancel out all of the waves. This is what
happens when two polarizing filters are combined at a 90-degree angle—no light passes through.
Now, what would happen if you added a third fence between the two fences with the
slats at a 45-degree angle? Well, it would sort of “twist” some of the shakes in the rope
so that the waves could then get through. The same thing is true with the polarizing
filters. The third filter twists some of the light so that it gets through. If you’re really
feeling scientific, go to any teacher’s supply store and pick up three polarizing filters for
about (US)$3 each and try it. It works.
Liquid crystals take advantage of the property of polarization. Liquid crystals are
composed of a specially formulated liquid full of long, thin crystals that always want to
orient themselves in the same direction, as shown in Figure 19-11. This substance acts
exactly like a liquid polarized filter. If you poured a thin film of this stuff between two
sheets of glass, you’d get a darn good pair of sunglasses.
Imagine cutting extremely fine grooves on one side of one of those sheets of glass.
When you place this liquid in contact with a finely grooved surface, the molecules naturally line up with the grooves in the surface (see Figure 19-12). ch19.indd 825 12/9/09 5:13:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 826 Figure 19-11
Waves of similar
orientation Figure 19-12
molecules tend to
line up together. If you place another finely grooved surface, with the grooves at a 90-degree orientation to the other surface, opposite of the first one, the molecules in contact with that
side will attempt to line up with it. The molecules in between, in trying to line up with
both sides, will immediately line up in a nice twist (see Figure 19-13). If two perpendicular polarizing filters are then placed on either side of the liquid crystal, the liquid
crystal will twist the light and enable it to pass (see Figure 19-14).
If you expose the liquid crystal to an electrical potential, however, the crystals will
change their orientation to match the direction of the electrical field. The twist goes
away and no light passes through (see Figure 19-15).
A color LCD screen is composed of a large number of tiny liquid crystal molecules
(called sub-pixels) arranged in rows and columns between polarizing filters. A translucent sheet above the sub-pixels is colored red, green, or blue. Each tiny distinct group
of three sub-pixels—one red, one green, and one blue—form a physical pixel, as shown
in Figure 19-16. ch19.indd 826 12/9/09 5:13:58 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 827 Figure 19-13 Liquid crystal molecules twisting Figure 19-14 No charge, enabling light to pass NOTE LCD pixels are very different from the pixels in a CRT. A CRT pixel’s
size changes depending on the resolution. The pixels in an LCD panel are
fixed and cannot be changed. See the section called “LCD Resolution” later in
the chapter for the scoop.
Once all of the pixels are laid out, how do you charge the right spots to make an
image? Early LCDs didn’t use rectangular pixels. Instead, images were composed of ch19.indd 827 12/9/09 5:14:02 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 828 Figure 19-15 Electrical charge, no light is able to pass Figure 19-16
LCD pixels different-shaped elements, each electrically separate from the others. To create an image, each area was charged at the same time. Figure 19-17 shows the number zero, a
display made possible by charging six areas to make an ellipse of sorts. This process,
called static charging, is still quite popular in more basic numeric displays such as calculators.
The static method would not work in PCs due to its inherent inflexibility. Instead,
LCD screens use a matrix of wires (see Figure 19-18). The vertical wires, the Y wires,
run to every sub-pixel in the column. The horizontal wires, the X wires, run along an
entire row of sub-pixels. There must be a charge on both the X and the Y wires to make
enough voltage to light a single sub-pixel. ch19.indd 828 12/9/09 5:14:06 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 829 Figure 19-17
for static LCD
numeric display Figure 19-18
An LCD matrix
of wires If you want color, you have three matrices. The three matrices intersect very close together. Above the intersections, the glass is covered with tiny red, green, and blue dots.
Varying the amount of voltage on the wires makes different levels of red, green, and
blue, creating colors (see Figure 19-19).
We call this usage of LCD technology passive matrix. All LCD displays on PCs used
only passive matrix for many years. Unfortunately, passive matrix is slow and tends
to create a little overlap between individual pixels. This gives a slightly blurred effect
to the image displayed. Manufacturers eventually came up with a speedier method of
display, called dual-scan passive matrix, in which the screen refreshed two lines at a time. ch19.indd 829 12/9/09 5:14:09 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 830 Figure 19-19
display Although other LCD technologies have since appeared, dual-scan continues to show up
on some lower-end LCD panels.
NOTE You’ll also find passive matrix displays in smaller, handheld devices.
See Chapter 21, “Portable Computing,” for details about handheld computing
devices. Thin Film Transistor
A vast improvement over dual scan is called thin film transistor (TFT) or active matrix
(Figure 19-20). Instead of using X and Y wires, one or more tiny transistors control
each color dot, providing faster picture display, crisp definition, and much tighter color
control. TFT is the LCD of choice today, even though it is much more expensive than
display LCD Components
The typical LCD projector is composed of three main components: the LCD panel,
the backlight(s), and the inverters. The LCD panel creates the image, the backlights
illuminate the image so you can see it, and the inverters send power to the backlights.
Figure 19-21 shows a typical layout for the internal components of an LCD monitor.
One of the great challenges to LCD power stems from the fact that the backlights
need AC power while the electronics need DC power. The figure shows one of the many ch19.indd 830 12/9/09 5:14:11 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 831 Figure 19-21 LCD internals ways that LCD monitor makers handle this issue. The AC power from your wall socket
goes into an AC/DC transformer that changes the power to DC. The LCD panel uses
this DC power.
Note in Figure 19-21 that this monitor has two backlights: one at the top and one at the
bottom. Most LCDs have two backlights, although many only have one. All LCD backlights use cold cathode fluorescent lamp (CCFL) technology, popular for its low power
use, even brightness, and long life. Figure 19-22 shows a CCFL from an LCD panel.
CCFL backlight ch19.indd 831 12/9/09 5:14:13 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 832 CCFLs need AC power to operate, but given that the transformer converts the incoming AC power to DC, each CCFL backlight needs a device called an inverter to convert
the DC power back into AC. Figure 19-23 shows a typical inverter used in an LCD. Figure 19-23
Inverter Looking once again at Figure 19-21, note the DVI and VGA inputs. DVI is a digital
signal, so it connects directly to the LCD’s logic circuitry. The VGA goes to an analog to
digital converter before reaching the LCD logic board.
Keep in mind that Figure 19-21 is a generic illustration. The actual location and
interconnections of the components are as variable as the number of LCD panels available today! LCD Resolution All LCD monitors have a native resolution, such as 1680 × 1050, that enables them
to display the sharpest picture possible. As mentioned earlier, the pixels are fixed. You
simply cannot run an LCD monitor at a resolution higher than the native one. Worse,
because LCDs have no equivalent to a shadow mask, they can’t run at a lower than native resolution without severely degrading image quality. A CRT can simply use more
dots and the filtering and smoothing of the shadow mask to make a picture at a lower
resolution look as good and crisp as the same picture at a higher resolution, but an LCD
cannot. The LCD has to use an edge-blurring technique called anti-aliasing to soften the
jagged corners of the pixels when running at lower than native resolution, which simply does not look as good. The bottom line? Always set the LCD at native resolution!
NOTE Two LCD panels that have the same physical size may have different
native resolutions. The hard-wired nature of LCD resolution creates a problem for techs and consumers
when dealing with bigger, better-quality monitors. A typical 15-inch LCD has a 1024 ×
768 resolution, but a 17-inch usually has 1280 × 1024 or higher. These high resolutions make the menus and fonts on a monitor super tiny, a problem for people with
less-than-stellar vision. Many folks throw in the towel and run these high-end LCDs at
lower resolution and just live with the lower-quality picture, but that’s not the best way
to resolve this problem. ch19.indd 832 12/9/09 5:14:14 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 833 With Windows XP (and to a lesser extent with the earlier versions of Windows),
Microsoft allows incredible customizing of the interface. You can change the font size,
shape, and color. You can resize the icons, toolbars, and more. You can even change
the number of dots per inch (DPI) for the full screen, making everything bigger or
For basic customizing, start at the Control Panel | Display applet | Appearance tab
or Control Panel | Personalization applet. To change the DPI for the display, go to the
Settings tab and click the Advanced button in Windows XP; in Windows Vista, just click
the Adjust font size (DPI) option in the Tasks list. Your clients will thank you! Brightness
The strength of an LCD monitor’s backlights determines the brightness of the monitor.
The brightness is measured in nits. LCD panels vary from 100 nits on the low end to
over 1000 nits or more on the high end. Average LCD panels are around 300 nits, which
most monitor authorities consider excellent brightness.
NOTE One nit equals one candela/m2. One candela is roughly equal to the
amount of light created by a candle. Response Rate
An LCD panel’s response rate is the amount of time it takes for all of the sub-pixels on
the panel to go from pure black to pure white and back again. This is roughly the same
concept as the CRT refresh rate, but with one important difference. Once the electron
gun on a CRT lights a phosphor, that phosphor begins to fade until it is lit again. Individual LCD sub-pixels hold their intensity until the LCD circuitry changes that subpixel, making the problem of flicker nonexistent on LCDs.
Manufacturers measure LCD response rates in milliseconds, with lower being better.
A typical lower-end or older LCD has a response rate of 20–25 ms. The screens look
fine, but you’ll get some ghosting if you try to watch a movie or play a fast-paced video
game. In recent years, manufacturers have figured out how to overcome this issue, and
you can find many LCD monitors with a response rate of 6–8 ms. Refresh Rate
The refresh rate for an LCD monitor uses numbers similar to that for a CRT monitor,
such as 60 Hz, but the terms mean slightly different things between the two technologies. With CRTs, as you’ll recall, the phosphors on the screen start to lose their glow and
need to be hit again by the electron guns many times per second to achieve an unwavering or flicker-free image. Each dot on an active matrix LCD, in contrast, has its own
transistor to light it up. There’s no need to freshen up the dot; it’s on or off. Regardless
of the refresh rate for the LCD, therefore, there’s never any flicker at all.
The refresh rate for an LCD monitor refers to how often a screen can change or update
completely. Think of the refresh rate as a metronome or timer and you’ll be closer to ch19.indd 833 12/9/09 5:14:14 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 834 how it works in an LCD. For most computing issues, 60 Hz is fine and that’s been the
standard for the industry. Humans see things that change as infrequently as 24 times per
second—the standard for motion pictures at the cinema, for example, and the best highdefinition (HD) signal—as a full motion video. To be able to change almost three times
faster is perfectly acceptable, even in higher-end applications such as fast-moving games.
Monitor manufacturers have released 120-Hz LCD monitors in a response to the
convergence of LCDs, televisions, and computers to enable you to see HD movies
or standard-definition (SD) content without any problems or visual artifacts on an
LCD monitor. The easiest number that provides a whole-number division for both
24 frames per second and 30 frames per second was 120 Hz. The latter is the standard
for SD content.
NOTE A video card needs to be able to support Dual-Link DVI to run a
120-Hz monitor or television. See the discussion on DVI later in this chapter
for details. Contrast Ratio
A big drawback of LCD monitors is that they don’t have nearly the color saturation or
richness of contrast of a good CRT monitoralthough LCD technology continues to
improve every year. A good contrast ratio—the difference between the darkest and lightest spots that the monitor can display—is 450:1, although a quick trip to a computer
store will reveal LCDs with lower levels (250:1) and higher levels (1000:1).
LCD monitor manufacturers market a dynamic contrast ratio number for their monitors, which measures the difference between a full-on, all-white screen, full-off, or allblack screen. This yields a much higher number than the standard contrast ratio. My
Samsung panels have a 1000:1 contrast ratio, for example, but a 20,000:1 dynamic
contrast ratio. Sounds awesome, right? In general, the dynamic contrast ratio doesn’t
affect viewing on computer monitors. Focus on the standard contrast ratio when making decisions on LCD screens. Projectors
Projectors are a third option for displaying your computer images and the best choice
when displaying to an audience or in a classroom. There are two ways to project an
image on a screen: rearview and front-view. As the name would suggest, a rearview projector (Figure 19-24) shoots an image onto a screen from the rear. Rearview projectors
are always self-enclosed and very popular for televisions, but are virtually unheard of
in the PC world.
A front-view projector shoots the image out the front and counts on you to put a
screen in front at the proper distance. Front-view projectors connected to PCs running
Microsoft PowerPoint have been the cornerstone of every meeting almost everywhere
for at least the past ten years (Figure 19-25). This section deals exclusively with frontview projectors that connect to PCs. ch19.indd 834 12/9/09 5:14:14 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 835 Figure 19-24
Rearview projector (photo courtesy of Samsung) Figure 19-25
of Dell Inc.) Projector Technologies
Projectors that connect to PCs have been in existence for almost as long as PCs themselves. Given all that time, a number of technologies have been used in projectors. The
first generation of projectors used CRTs. Each color used a separate CRT that projected
the image onto a screen (Figure 19-26). CRT projectors create beautiful images but are
expensive, large, and very heavy, and have for the most part been abandoned for more
Given that light shines through an LCD panel, LCD projectors are a natural fit for
front projection. LCD projectors are light and very inexpensive compared to CRTs but
lack the image quality. LCD projectors are so light that almost all portable projectors
use LCD (Figure 19-27). ch19.indd 835 12/9/09 5:14:15 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 836 Figure 19-26
CRT projector Figure 19-27
of ViewSonic) NOTE Another type of technology that’s seen in projectors but is outside
the scope of the CompTIA A+ exams is called digital light processing (DLP).
Check out the “Beyond A+” section of this chapter for details.
All projectors share the same issues as their equivalent technology monitors. LCD
projectors have a specific native resolution, for example. In addition, you need to understand three concepts specific to projectors: lumens, throw, and lamps. Lumens
The brightness of a projector is measured in lumens. A lumen is the amount of light
given off by a light source from a certain angle that is perceived by the human eye.
The greater the lumen rating of a projector, the brighter the projector will be. The best
lumen rating depends on the size of the room and the amount of light in the room.
There’s no single answer for “the right lumen rating” for a projector, but use this as a
rough guide. If you use a projector in a small, darkened room, 1000 to 1500 lumens ch19.indd 836 12/9/09 5:14:16 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 837 will work well. If you use a projector in a mid-sized room with typical lighting, you’ll
need at least 2000 lumens. Projectors for large rooms have ratings over 10,000 lumens
and are very expensive. Throw
A projector’s throw is the size of the image at a certain distance from the screen. All projectors have a recommended minimum and maximum throw distance that you need to
take into consideration. A typical throw would be expressed as follows. A projector with
a 16:9 image-aspect ratio needs to be 11 to 12 feet away from the projection surface to
create a 100-inch diagonal screen. A long throw lens has about a 1:2 ratio of screen size
to distance, so to display a 4-foot screen, you’d have to put the projector 8 feet away.
Some short throw lenses drop that ratio down as low as 1:1! Lamps
The bane of every projector is the lamp. Lamps work hard in your projector, as they
must generate a tremendous amount of light. As a result, they generate quite a bit of
heat, and all projectors come with a fan to keep the lamp from overheating. When you
turn off a projector, the fan continues to run until the lamp is fully cooled. Lamps are
also expensive, usually in the range of a few hundred dollars (U.S.), which comes as a
nasty shock to someone who’s not prepared for that price when the lamp dies! Common Features
CRT or LCD, all monitors share a number of characteristics that you need to know for
purchase, installation, maintenance, and troubleshooting. Size
You need to take care when buying CRT monitors. CRT monitors come in a large number of sizes, all measured in inches (although most metric countries provide the metric
equivalent value). All monitors provide two numbers: the monitor size and the actual
size of the screen. The monitor size measures from two opposite diagonal corners. The
actual screen is measured from one edge of the screen to the opposite diagonal side.
This latter measurement is often referred to as the viewable image size (VIS). You will
commonly see a size difference of one-to-two inches between the two measurements
(see Figure 19-28). A 17-inch CRT monitor, for example, might have a 15.5-inch VIS.
size of a CRT Monitor size ch19.indd 837 Viewable image size 12/9/09 5:14:17 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 838 LCD monitors dispense with the two values and simply express the VIS value. You
must consider this issue when comparing LCDs to CRTs. A 15-inch LCD monitor will
have about the same viewing area as a 17-inch CRT. Connections
CRT monitors for PCs all use the famous 15-pin, three-row, DB-type connector (see
Figure 19-29) and a power plug. The DB connector is also called a D-shell or D-subminiature connector. Larger or multipurpose monitors may have a few other connectors,
but as far as the CRT is concerned, these are the only two you need for video. Figure 19-29
CRT connector NOTE You’ll often hear the terms flat-panel display or LCD panel to describe
LCD monitors. I prefer the term LCD monitor, but you should be prepared to
hear it a few different ways.
Unlike the analog CRTs, LCD monitors need a digital signal. This creates somewhat
of an issue. The video information stored on a video card’s RAM is clearly digital. All
VGA and better video cards include a special chip (or function embedded into a chip
that does several other jobs) called the random access memory digital-to-analog converter
(RAMDAC). As the name implies, RAMDAC takes the digital signal from the video card
and turns it into an analog signal for the analog CRT (see Figure 19-30). The RAMDAC
really defines the bandwidth that the video card outputs.
Well, RAMDACs certainly make sense for analog CRT monitors. However, if you
want to plug your LCD monitor into a regular video card, you need circuitry on the
LCD monitor to convert the signal from analog to digital (see Figure 19-31).
Many LCD monitors use exactly this process. These are called analog LCD monitors. The
monitor really isn’t analog; it’s digital, but it takes a standard VGA input. These monitors have one advantage: You may use any standard VGA video card. But these monitors
require adjustment of the analog timing signal to the digital clock inside the monitor. ch19.indd 838 12/9/09 5:14:17 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 839 Figure 19-30 An analog signal sent to a CRT monitor This used to be a fairly painful process, but most analog LCD monitors now include intelligent circuitry to make this process either automatic or very easy.
Why convert the signal from digital to analog and then back to digital? Well, many
monitor and video card people agree that it just doesn’t make much sense. We now
see quite a few digital LCD monitors and digital video cards. They use a completely
different connector than the old 15-pin DB connector used on analog video cards and
monitors. After a few false starts with connection standards, under names such as P&D
and DFP, the digital LCD world, with a few holdouts, moved to the digital visual interface
(DVI) standard. DVI is actually three different connectors that look very much alike:
DVI-D is for digital, DVI-A is for analog (for backward compatibility if the monitor
maker so desires), and the DVI-A/D or DVI-I (interchangeable) accepts either a DVI-D
or DVI-A. DVI-D and DVI-A are keyed so that they will not connect.
DVI-D and DVI-I connectors come in two varieties, single-link and dual-link. Singlelink DVI has a maximum bandwidth of 165 MHz, which, translated into practical terms,
limits the maximum resolution of a monitor to 1920 × 1080 at 60 Hz or 1280 × 1024 at
85 Hz. Dual-link DVI uses more pins to double throughput and thus grant higher resolutions (Figure 19-32). With dual link, you can have displays up to a whopping 2048 ×
1536 at 60 Hz! ch19.indd 839 12/9/09 5:14:20 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 840 Figure 19-31 Converting analog back to digital on the LCD Figure 19-32
connector NOTE You can plug a single-link DVI monitor into a dual-link DVI connector
and it’ll work just fine.
Digital connectors are quickly replacing analog in the monitor world. Digital makes
both the monitor and the video card cheaper, provides a clearer signal because no conversion is necessary, and makes installation easy. Many monitors and video cards these
days only support digital signals, but there are still quite a few of each that provide both
digital and analog connections. ch19.indd 840 12/9/09 5:14:25 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 841 The video card people have it easy. They either include both a VGA and a DVI-D connector or they use a DVI-I connector. The advantage to DVI-I is that you can add a cheap
DVI-I to VGA adapter (one usually comes with the video card) like the one shown in
Figure 19-33 and connect an analog monitor just fine. Figure 19-33
DVI to VGA
adapter NOTE Video cards with two video connectors support dual monitors. See
the “Dual Monitors” section later in this chapter. Monitor makers have it tougher. Most LCD monitor makers have made the jump to
DVI, but many include a VGA connector for those machines that still need it.
Unless you’re buying a complete new system, you’ll rarely buy a video card at the
same time you buy a monitor. When you’re buying a monitor or a video card, make
sure that the new device will connect to the other! Adjustments
Most adjustments to the monitor take place at installation, but for now, let’s just make
sure you know what they are and where they are located. Clearly, all monitors have an
On/Off button or switch. Also, see if you can locate the Brightness and Contrast buttons. Beyond that, most monitors (at least the only ones you should buy) have an onboard menu system, enabling a number of adjustments. Every monitor maker provides
a different way to access these menus, but they all provide two main functions: physical
screen adjustment (bigger, smaller, move to the left, right, up, down, and others) and
color adjustment. The color adjustment lets you adjust the red, green, and blue guns to
give you the best color tones. All of these settings are a matter of personal taste. Make
sure the person who will use the computer understands how to adjust these settings
(see Figure 19-34). ch19.indd 841 12/9/09 5:14:26 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 842 Figure 19-34
controls Power Conservation
CRT and LCD monitors differ greatly in the amount of electricity they require. The bottom line is that CRTs use a lot and LCDs use a lot less. Here’s the scoop.
Approximately half the power required to run a desktop PC is consumed by the
CRT monitor. Monitors that meet the Video Electronics Standards Association (VESA)
specification for display power-management signaling (DPMS) can reduce monitor power
consumption by roughly 75 percent. This is accomplished by reducing or eliminating
the signals sent by the video card to the monitor during idle periods. By eliminating
these pulses, the monitor essentially takes catnaps. The advantage over simply shutting
the monitor off is in the time it takes to restore the display.
A typical CRT monitor consumes approximately 120 watts. During a catnap or powerdown mode, the energy consumption is reduced to below 25 watts, while enabling the
screen to return to use in less than ten seconds. Full shutoff is accomplished by eliminating all clocking pulses to the monitor. Although this reduces power consumption
to below 15 watts, it also requires anywhere from 15 to 30 seconds to restore a usable
A typical LCD monitor, in contrast, uses less than half the electricity that a CRT uses.
A 19-inch, 4:3 aspect-ratio flat panel, for example, uses around 33 watts at peak usage
and less than 2 watts in DPMS mode. Larger LCDs use more power at peak usage than
smaller ones. A 21-inch wide-screen model, for example, might draw ~75 watts at peak
but drop down to less than 2 watts in DPMS mode. Swapping out CRTs with LCDs is a
great way to save on your electric bill! Video Cards
The video card, or display adapter, handles the video chores within the PC, processing
information from the CPU and sending it out to the monitor. The video card is composed of two major pieces: the video RAM and the video processor circuitry. The video
RAM stores the video image. On the first video cards, this RAM was good old dynamic ch19.indd 842 12/9/09 5:14:27 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 843 RAM (DRAM), just like the RAM on the motherboard. Today’s video cards often have
better RAM than your system has! The video processing circuitry takes the information
on the video RAM and shoots it out to the monitor. Although early video processing
circuitry was little more than an intermediary between the CPU and the video RAM,
modern video processors are more powerful than all but the latest CPUs! It’s not at
all uncommon to see video cards that need fans to cool their onboard processors (see
Figure 19-35). Figure 19-35
Video card with
a cooling fan This section looks at five aspects that define a video card: display modes, motherboard connection, graphics processor circuitry, video memory, and connections. Modes
The trick to understanding video cards is to appreciate the beginnings and evolution of
video. Video output to computers was around long before PCs were created. At the time
PCs became popular, video was almost exclusively text-based, meaning that the only
image the video card could place on the monitor was one of the 256 ASCII characters.
These characters were made up of patterns of pixels that were stored in the system BIOS.
When a program wanted to make a character, it talked to DOS or to the BIOS, which
stored the image of that character in the video memory. The character then appeared
on the screen.
The beauty of text video cards was that they were simple to use and cheap to make.
The simplicity was based on the fact that only 256 characters existed, and no color
choices were available—just monochrome text.
You could, however, choose to make the character bright, dim, normal, underlined,
or blinking. Positioning the characters was easy, as space on the screen allowed for only
80 characters per row and 24 rows of characters.
Long ago, RAM was very expensive, so video card makers were interested in using the
absolute least amount of RAM possible. Making a monochrome text video card was a
great way to keep down RAM costs. Let’s consider this for a minute. First, the video RAM ch19.indd 843 12/9/09 5:14:27 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 844 is where the contents of the screen are located. You need enough video RAM to hold all
of the necessary information for a completely full screen. Each ASCII character needs
eight bits (by definition), so a monitor with 80 characters/row and 24 rows will need
80 characters × 24 rows = 1920 characters = 15,360 bits or 1920 bytes
The video card would need less than 2000 bytes of memory, which isn’t much, not even
in 1981 when the PC first came out. Now, be warned that I’m glossing over a few things—
where you store the information about underlines, blinking, and so on. The bottom line is
that the tiny amount of necessary RAM kept monochrome text video cards cheap.
Very early on in the life of PCs, a new type of video, called a graphics video card, was
invented. It was quite similar to a text card. The text card, however, was limited to the
256 ASCII characters, whereas a graphics video card enabled programs to turn any
pixel on the screen on or off. It was still monochrome, but programs could access any
individual pixel, enabling much more creative control of the screen. Of course, it took
more video RAM. The first graphics cards ran at 320 × 200 pixels. One bit was needed
for each pixel (on or off), so
320 × 200 = 64,000 bits or 8000 bytes
That’s a lot more RAM than was needed for text, but it was still a pretty low amount
of RAM—even in the old days. As resolutions increased, however, the amount of video
RAM needed to store this information also increased.
After monochrome video was invented, moving into color for both text and graphics
video cards was a relatively easy step. The only question was how to store color information for each character (text cards) or pixel (graphics cards). This was easy—just set
aside a few more bits for each pixel or character. So now the question becomes, “How
many bits do you set aside?” Well, that depends on how many colors you want. Basically, the number of colors determines the number of bits. For example, if you want
four colors, you need 2 bits (2 bits per pixel). Then, you could do something like this
00 = black 01 = cyan (blue) 10 = magenta (reddish pink) 11 = white So if you set aside 2 bits, you could get four colors. If you want 16 colors, set aside
4 bits, which would make 16 different combinations. Nobody ever invented a text
mode that used more than 16 colors, so let’s start thinking in terms of only graphics
mode and bits per pixels. To get 256 colors, each pixel would have to be represented
with 8 bits. In PCs, the number of colors—called the color depth—is always a power of
2: 4, 16, 256, 64 K, and so on. Note that as more colors are added, more video RAM
is needed to store the information. Here are the most common color depths and the
number of bits necessary to store the color information per pixel:
2 colors = 1 bit (mono)
4 colors = 2 bits
16 colors = 4 bits ch19.indd 844 12/9/09 5:14:28 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 845 256 colors = 8 bits
64 K colors = 16 bits
16.7 million colors = 24 bits
Most technicians won’t say, for example, “I set my video card to show over 16 million colors.” Instead, they’ll say, “I set my color depth to 24 bits.” Talk in terms of bits,
not colors. It is assumed that you know the number of colors for any color depth.
You can set the color depth for a Windows 2000 or Windows XP computer in the
Display Properties applet on the Settings tab (Figure 19-36). If you set up a typical Windows XP computer, you’ll notice that Windows offers you 32-bit color quality, which
might make you assume you’re about to crank out more than 4 billion colors, but that’s
simply not the case. The 32-bit color setting offers 24-bit color plus an 8-bit alpha channel. An alpha channel controls the opacity of a particular color. By using an alpha channel, Windows can more effectively blend colors to create the effect of semi-transparent
images. In Windows XP, you see this in the drop shadow under a menu; in Windows
Vista, almost every screen element can be semi-transparent (Figure 19-37).
Your video card and monitor are capable of showing Windows in a fixed number
of different resolutions and color depths. The choices depend on the resolutions and
color depths the video card can push to the monitor and the amount of bandwidth
your monitor can support. Any single combination of resolution and color depth you
set for your system is called a mode. For standardization, VESA defines a certain number
of resolutions, all derived from the granddaddy of video modes: VGA. Figure 19-36
settings in Windows XP ch19.indd 845 12/9/09 5:14:28 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 846 Figure 19-37 Semi-transparency in Windows Vista VGA
With the introduction of the PS/2, IBM introduced the video graphics array (VGA) standard. This standard offered 16 colors at a resolution of 640 × 480 pixels. VGA supported
such an amazing variety of colors by using an analog video signal instead of a digital
one, as was the case prior to the VGA standard. A digital signal is either all on or all off.
By using an analog signal, the VGA standard can provide 64 distinct levels for the three
colors (RGB)—that is, 643 or 262,144 possible colors—although only 16 or 256 can be
seen at a time. For most purposes, 640 × 480 and 16 colors defines VGA mode. This is
typically the display resolution and color depth referred to on many software packages
as a minimum display requirement. Every video card made in the past 15 years can
output as VGA, but VGA-only cards are now obsolete. Beyond VGA
The 1980s were a strange time for video. Until the very late 1980s, VGA was the highest mode defined by VESA, but demand grew for modes that went beyond VGA. This
motivated VESA to introduce (over time) a number of new modes with names such as
SVGA, XGA, and many others. Even today, new modes are being released! Table 19-1
shows the more common modes. ch19.indd 846 12/9/09 5:14:29 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 847 Video Mode Resolution Aspect Ratio Typical Device 800 × 600 4:3 Small monitors HDTV 720p 1280 × 720 16:9 Lowest resolution that can be called HDTV SXGA 1280 × 1024 5:4 Native resolution for many desktop LCD
monitors WSXGA 1440 × 900 16:10 Widescreen laptops SXGA+ 1400 × 1050 4:3 Laptop monitors and high-end projectors UXGA 1600 × 1200 4:3 Larger CRT monitors HDTV 1080p 1920 × 1080 16:9 Full HDTV resolution WUXGA 1920 × 1200 16:10 For 24" widescreen monitors SVGA Table 19-1 Typical Display Modes The video card must have sufficient RAM to support each combination of color
depth and resolution. Many years ago this mattered, when video cards had scant megabytes of memory. A video card with only 2 MB of RAM, for example, could handle a
high color (16-bit) display at 1024 × 768, but not the same resolution with true color
(24-bit). Table 19-2 shows common modes and the minimum video memory needed.
All modern video cards can handle true color at any resolution. Resolution 16-bit (high color) 24-bit (true color) 640 × 480 1 MB 1 MB 800 × 600 1 MB 2 MB 1024 × 768 2 MB 4 MB 1280 × 1024 4 MB 4 MB 1600 × 1200 4 MB 6 MB Table 19-2 Common modes and the minimum video memory required EXAM TIP To accommodate rotated LCD monitors in portrait view, the
video resolution numbers might be reversed. Rather than 1280 × 1024, for
example, you might see 1024 × 1280. The amount of RAM needed remains
the same regardless. Motherboard Connection
Using more color depth slows down video functions. Data moving from the video card
to the display has to go through the video card’s memory chips and the expansion bus,
and this can happen only so quickly. The standard PCI slots used in almost all systems ch19.indd 847 12/9/09 5:14:30 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 848 are limited to 32-bit transfers at roughly 33 MHz, yielding a maximum bandwidth of
132 MBps. This sounds like a lot until you start using higher resolutions, high color
depths, and higher refresh rates.
For example, take a typical display at 800 600 with a fairly low refresh of 70 Hz.
The 70 Hz means the display screen is being redrawn 70 times per second. If you use
a low color depth of 256 colors, which is 8 bits (28 = 256), you can multiply all of the
values together to see how much data per second has to be sent to the display:
800 × 600 × 1 byte × 70 = 33.6 MBps
If you use the same example at 16 million (24-bit) colors, the figure jumps to
100.8 MBps. You might say, “Well, if PCI runs at 132 MBps, it can handle that!” That
statement would be true if the PCI bus had nothing else to do but tend to the video
card, but almost every system has more than one PCI device, each requiring part of that
throughput. The PCI bus simply cannot handle the needs of many current systems. AGP
Intel answered the desire for video bandwidth even higher than PCI with the Accelerated
Graphics Port (AGP). AGP is a single, special port, similar to a PCI slot, that is dedicated
to video. You will never see a motherboard with two AGP slots. Figure 19-38 shows an
early-generation AGP. AGP is derived from the 66-MHz, 32-bit PCI 2.1 specification.
AGP uses a function called strobing that increases the signals two, four, and eight times
for each clock cycle.
AGP Simply describing AGP as a faster PCI would seriously misrepresent the power of
AGP. AGP has several technological advantages over PCI, including the bus, the internal
operations, and the capability to handle 3-D texturing.
First, AGP currently resides alone, on its own personal data bus, connected directly
to the Northbridge (see Figure 19-39). This is important because more advanced versions of AGP outperform every bus on the system except the frontside bus!
Second, AGP takes advantage of pipelining commands, similar to the way CPUs
pipeline. Third, AGP has a feature called sidebanding—basically a second data bus that ch19.indd 848 12/9/09 5:14:30 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 849 Figure 19-39 An AGP bus enables the video card to send more commands to the Northbridge while receiving
other commands at the same time.
Video cards do all kinds of neat stuff with their RAM; for example, video cards store
copies of individual windows so they can display the windows at different points on
the screen very quickly. A demanding application can quickly max out the onboard
RAM on a video card, so AGP provides a pathway so the AGP card can “steal” chunks
of the regular system memory to store video information, especially textures. This is
generically called a system memory access and is quite popular.
NOTE Intel couldn’t quite bring itself to call AGP’s system memory access…
err…system memory access, so they use a couple of different terms. The
video processor maps out a portion of system memory by using the Graphics
Address Remapping Table (GART). The size of the remapped region is called the
AGP aperture. A typical AGP aperture is 32 MB or 64 MB.
AGP has gone through three sets of specifications (AGP1.0, AGP2.0, and AGP3.0),
but the official names tend to be ignored. Most techs and consumers refer to the various cards by their strobe multiplier, such as AGP 1×, 2×, 4×, and 8×. The only problem
with blurring the distinctions between the specifications comes from the fact that many
new motherboards simply don’t support the older AGP cards because the older cards
require a different physical connection than the new ones.
Some motherboards support multiple types of AGP. Figure 19-40 shows an AGP slot
that accommodates everything up to 8×, even the very rare AGP Pro cards. Note that the
tab on the slot covers the extra pins required for AGP Pro.
Because many AGP cards will run on older AGP motherboards, you can get away
with mixing AGP specifications. To get the best, most stable performance possible, you
should use an AGP card that’s fully supported by the motherboard. ch19.indd 849 12/9/09 5:14:32 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 850 Figure 19-40
AGP 8× slot The only significant downside to AGP lies in the close connection tolerances required by the cards themselves. It’s very common to snap in a new AGP card and power
up just to get a no-video-card beep or a system that doesn’t boot. Always take the time
to ensure that an AGP card is snapped down securely and screwed in before starting
the system. PCIe
AGP is a great way to get video information to and from video cards very quickly, but
it has the downside of being a unique connector in a world where saving money is important. AGP, being based on PCI, also uses a parallel interface. When the PCI Express
(PCIe) interface was developed to replace PCI, the PCIe designers worked hard to make
sure it would also replace AGP. PCIe is a natural evolution for video because it is incredibly fast, using a serial communication method. Also, because PCIe is a true expansion
bus designed to talk to the CPU and RAM, it also supports all of the little extras found
in AGP, such as sidebanding and system memory access. All PCIe video cards use the
PCIe ×16 connector (Figure 19-41). PCIe replaced AGP as the primary video interface
almost overnight. Figure 19-41
PCIe video card
PCIe slot ch19.indd 850 12/9/09 5:14:34 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 851 Graphics Processor
The graphics processor handles the heavy lifting of taking commands from the CPU
and translating them into coordinates and color information that the monitor understands and displays.
Video card discussion, at least among techs, almost always revolves around the
graphics processor they use and the amount of RAM onboard. A typical video card
might be called an ATI Radeon X1950 XTX 512 MB, so let’s break that down. ATI is the
manufacturer, Radeon X1950 XTX is the model of the card as well as the graphics processor, and 512 MB is the amount of video RAM.
Many companies make the hundreds of different video cards on the market, but only
two companies produce the vast majority of graphics processors found on video cards:
NVIDIA and ATI. NVIDIA and ATI make and sell graphics processors to third-party
manufacturers who then design, build, and sell video cards under their own branding.
ATI also makes and sells its own line of cards. Figure 19-42 shows an NVIDIA GeForce
GTX 260 on a board made by EVGA.
GTX 260 Your choice of graphics processor is your single most important decision in buying
a video card. Low-end graphics processors usually work fine for the run-of-the-mill
user who wants to write letters or run a Web browser. High-end graphics processors are
designed to support the beautiful 3-D games that are so popular today.
NVIDIA and ATI are extremely competitive, and both companies introduce multiple
models of graphics processors (and therefore new models of cards) every year. However, unless you’re using the Vista Aero glass desktop, all of these extra features you see in
video cards are really only for the true driving force in video cards: 3-D gaming. Your PC
is capable of providing you with hours of incredible entertainment via a huge number
of popular games that immerse you in 3-D environments full of light, shadows, explosions, and other amazing effects that create a fun and beautiful gaming experience.
These 3-D games have special needs to do all this amazing stuff. One need is textures.
A texture is a small picture that is tiled over and over again on walls, floors, and other
surfaces to create the 3-D world. Take a look at the wall in Figure 19-43. It’s made up of
only three textures that are repeated over and over on the surface. ch19.indd 851 12/9/09 5:14:34 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 852 Figure 19-43
Wall of textures Games also use hundreds of lighting effects such as transparency (water), shadows,
reflection, and bump mapping—the process of laying multiple textures on the same
spot to give a more textured (bumpy) look to the surface. These games are where the
higher-quality graphics processors really shine. Learn more about 3-D issues in more
depth in the “3-D Graphics” section later in the chapter.
Choosing a graphics processor is a challenge because the video industry is constantly
coming out with new models. One of the best guides is price. The best (and newest)
graphics cards usually cost around (US)$400–500. The cheapest cards cost around $50.
I usually split the difference and go for a card priced around $180 to $200—such a card
will have most of the features you want without breaking your bank account.
If you use your computer only for 2-D programs (most office applications such as
word processors, e-mail, and Web browsers are 2-D), most of the features of the more
advanced graphics cards will do you little good. If you’re not a gamer, you can meet
your needs with a cheap, low-end video card. Video Memory
Video memory is crucial to the operation of a PC. It is probably the hardest-working
set of electronics on the PC. Video RAM constantly updates to reflect every change that
takes place on the screen. When you’re working with heavy-duty applications (such as
games), video memory can prove to be a serious bottleneck in three ways: data throughput speed, access speed, and simple capacity. ch19.indd 852 12/9/09 5:14:35 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 853 Manufacturers have overcome these bottlenecks by upping the width of the bus between the video RAM and video processor; using specialized, super-fast RAM; and adding more and more total RAM.
First, manufacturers reorganized the video display memory on cards from the typical 32-bit-wide structure to 64, 128, or even 256 bits wide. Because the system bus is
limited to 32 or 64 bits, this would not be of much benefit if video display cards weren’t
really coprocessor boards. Most of the graphics rendering and processing is handled on
the card by the video processor chip rather than by the CPU. The main system simply
provides the input data to the processor on the video card. Because the memory bus
on the video card is as much as eight times wider than the standard 32-bit pathway
(256 bits), data can be manipulated and then sent to the monitor much more quickly
(Figure 19-44). Figure 19-44 Wide path between video processor and video RAM Specialized types of video RAM have been developed for graphics cards, and many
offer substantial improvements in video speeds. The single most important feature that
separates DRAM from video RAM is that video RAM can read and write data at the same
time. Table 19-3 shows a list of common video memory technologies used yesterday
and today—make sure you know these for the exams! ch19.indd 853 12/9/09 5:14:36 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 854 Acronym Name Purpose VRAM Video RAM The original graphics RAM WRAM Window RAM Designed to replace VRAM; never caught on SGRAM Synchronous Graphics RAM A version of SDRAM with features to
speed up access for graphics DDR SDRAM Double Data Rate Synchronous
DRAM Used on budget graphics cards and very
common on laptop video cards DDR2 SDRAM Double Data Rate version 2,
Synchronous DRAM Popular on video cards until GDDR3; lower
voltage than DDR memory GDDR3 SDRAM Graphics Double Data Rate,
version 3 Similar to DDR2 but runs at faster speeds;
different cooling requirements GDDR4 SDRAM Graphics Double Data Rate,
version 4 Upgrade of GDDR3; faster clock GDDR5 SDRAM Graphics Double Data Rate,
version 5 Successor to GDDR4; double the input/
output rate of GDDR4 Table 19-3 Video RAM Technologies Finally, many advanced 3-D video cards come with huge amounts of video RAM. It’s
very common to see cards with 64, 128, 256, or 512 MB or even 1 GB of RAM! Why so
much? Even with PCI Express, accessing data in system RAM always takes a lot longer
than accessing data stored in local RAM on the video card. The huge amount of video
RAM enables game developers to optimize their games and store more essential data
on the local video RAM. Connections
Modern video cards offer connections to one or more PC monitors. Many also sport
connectors for non-monitors, such as televisions. The video card in Figure 19-45 has
three connectors: VGA, DVI-I, and S-video. Other connectors enable the video card to
connect to composite, component, and even high-definition devices. Figure 19-45
S-video, and DVI-I ch19.indd 854 12/9/09 5:14:37 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 855 For Standard Monitors
You know about the standard monitor connectors, VGA and DVI, from the monitor
discussion earlier. About the only thing to add is that most DVI connections on video
cards these days natively support analog signals. You can use a simple DVI-to-VGA
adapter, for example, for connecting a VGA cable to a video card.
Apple Macintosh desktop models use a DisplayPort connection rather than VGA or
DVI for connecting to a monitor. Dell offers support for DisplayPort as well at the time
of this writing. Figure 19-46 shows a DisplayPort jack on a Dell portable.
DisplayPort jack For Multimedia Devices
Video cards can have one or more standard connections plus non-standard connections
for hooking the PC to a multimedia device, such as a television, DVD player, or video
camera. The earliest type of connector commonly found is the S-video connector. This
provides decent-quality video output or, in some cases, input. More commonly now
you see both a proprietary round connector that supports S-video and a proprietary
dongle that adds support for video through either component connection or composite connections. Figure 19-47 shows the similar round ports.
S-video and proprietary round
S-video A composite connector provides a video signal through a single cable, whereas a
component adapter provides a split signal, red, green, and blue. Figure 19-48 shows the
two connector dongles. ch19.indd 855 12/9/09 5:14:38 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 856 Figure 19-48
component connection options The best connections for outputting to television are the High Definition Multimedia Interface (HDMI) connectors. Although a few devices offer HDMI output directly (such as the portable pictured in Figure 19-49), most video cards support HDMI
through a special cable that connects to a dual-link DVI port. Figure 19-50 shows an
example of such a cable.
HDMI port on
Lenovo laptop Figure 19-50
DVI to HDMI
cable NOTE Some video cards with built-in television tuners that enable the PC
to be a television as well as a computer have a standard coaxial jack for
connecting a cable or antenna. See Chapter 20, “Multimedia,” for the scoop
on TV tuners. ch19.indd 856 12/9/09 5:14:40 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 857 Installing and Configuring Video
Once you’ve decided on the features and price for your new video card or monitor, you
need to install them into your system. As long as you have the right connection to your
video card, installing a monitor is straightforward. The challenge comes when installing the video card.
During the physical installation of a video card, watch out for two possible issues:
long cards and proximity of the nearest PCI card. Some high-end video cards simply
won’t fit in certain cases or block access to needed motherboard connectors such as
the IDE sockets. There’s no clean fix for such a problem—you simply have to change
at least one of the components (video card, motherboard, or case). Because high-end
video cards run very hot, you don’t want them sitting right next to another card; make
sure the fan on the video card has plenty of ventilation space. A good practice is to leave
the slot next to the video card empty to allow better airflow (Figure 19-51). Figure 19-51
Installing a video
card Once you’ve properly installed the video card and connected it to the monitor, you’ve
conquered half the territory for making the video process work properly. You’re ready
to tackle the drivers and tweak the operating system, so let’s go! Software
Configuring your video software is usually a two-step process. First you need to load
drivers for the video card. Then you need to open the Control Panel and go to the
Display applet (Windows 2000/XP) or Personalization applet (Windows Vista/7) to
make your adjustments. Let’s explore how to make the video card and monitor work
in Windows. ch19.indd 857 12/9/09 5:14:41 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 858 Drivers
Just like any other piece of hardware, your video card needs a driver to function. Video
card drivers install pretty much the same way as all of the other drivers we’ve discussed
thus far: either the driver is already built into Windows or you must use the installation
CD that comes with the video card.
Video card makers are constantly updating their drivers. Odds are good that any
video card more than a few months old has at least one driver update. If possible, check
the manufacturer’s Web site and use the driver located there if there is one. If the Web
site doesn’t offer a driver, it’s usually best to use the installation CD. Always avoid using
the built-in Windows driver as it tends to be the most dated.
We’ll explore driver issues in more detail after we discuss the Display applet. Like so
many things about video, you can’t fully understand one topic without understanding
at least one other! Using the Display/Personalization Applet
With the driver installed, you’re ready to configure your display settings. The Display
applet or Personalization applet on the Control Panel is your next stop. The Display
applet and Personalization applet provide convenient, central locations for all of your display settings, including resolution, refresh rate, driver information, and color depth.
The default Display applet window in Windows XP, called the Display Properties
dialog box (Figure 19-52), has five tabs: Themes, Desktop, Screen Saver, Appearance,
and Settings. Earlier versions of Windows have a subset of these tabs. The first four
tabs have options you can choose to change the look and feel of Windows and set up
a screensaver; the fifth tab is where you make adjustments that relate directly to your
monitor and video card.
Display Properties dialog box in
Windows XP ch19.indd 858 12/9/09 5:14:41 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 859 The Personalization applet in Windows Vista offers functions similar to the Display
applet, but each function manifests as a clickable option rather than as a separate tab
(Figure 19-53). Four of the seven options mirror the look and feel options of earlier
versions of Windows, such as Window Color and Appearance, Desktop Background,
Screen Saver, and Theme. The last option, Display Settings, is where you make adjustments to your monitor and video card. Two options, Sounds and Mouse Pointers, don’t
concern us at all at this time. Figure 19-53 Personalization applet in Windows Vista Whether discussing tabs or options, the functions on both applets are pretty much
the same, so let’s do this in one discussion. I’ll point out any serious differences among
the versions. Making the Screen Pretty
Three tabs/options in the Display/Personalization applet have the job of adjusting
the appearance of the screen: Themes/Theme, Desktop/Desktop Background, and
Appearance/ Windows Color and Appearance. Windows themes are preset configurations of the look and feel of the entire Windows environment (Figure 19-54). ch19.indd 859 12/9/09 5:14:42 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 860 Figure 19-54 Theme option in the Personalization applet The Desktop tab/option (Figure 19-55) defines the background color or image. In
Windows XP, it also includes the handy Customize Desktop button that enables you to
define the icons as well as any Web pages you want to appear on the Desktop. Windows
Vista/7 give you the option to position the image on the screen (Figure 19-56), and the
Change desktop icons option on the Tasks list in the Personalization applet enables
you to choose which system icons (such as Computer, Recycle Bin, and Network) show
up on your desktop, as well as which graphical icons they use.
The last of the tabs for the look and feel of the desktop in Windows 2000/XP is the
Appearance tab. Think of the Appearance tab as the way to fine-tune the theme to your
liking. The main screen gives only a few optionsthe real power is when you click
the Advanced button (Figure 19-57). Using this dialog box, you may adjust almost
everything about the desktop, including the types of fonts and colors of every part of
The Window Color and Appearance option in Windows Vista/7 is a little simpler
on the surface, enabling you to change the color scheme, intensity, and transparency
(Figure 19-58). You can unlock the full gamut of options, though, by clicking the Open
classic appearance properties for more color options link. ch19.indd 860 12/9/09 5:14:42 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 861 Figure 19-55
Desktop tab on
Display Properties dialog box Figure 19-56 Desktop Background options in Windows Vista ch19.indd 861 12/9/09 5:14:43 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 862 Figure 19-57
dialog box Figure 19-58 Window Color and Appearance option ch19.indd 862 12/9/09 5:14:44 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 863 Screen Saver
At first glance, the Screen Saver tab/option seems to do nothing but set the Windows
screensaverno big deal, just about everyone has set a screensaver. But another option
on the Screen Saver tab gets you to one of the most important settings of your system:
power management. Click on the Power button or Change power settings option to get to
the Power Options Properties dialog box or Power Options applet (Figure 19-59). Figure 19-59 Power Options Properties dialog box The tabs and options define all of the power management of the system. Power management is a fairly involved process, so we’ll save the big discussion for where we need
to save power the most: Chapter 21, “Portable Computing.” Settings Tab/Display Settings Applet
The Settings tab or Display Settings applet (Figure 19-60) is the centralized location for
configuring all of your video settings. From the main screen you can adjust both the
resolution and the color depth. Windows only displays resolutions and color depths
that your video card/monitor combination can accept and that are suitable for most
situations. Everyone has a favorite resolution, and higher isn’t always better. Especially
for those with trouble seeing small screen elements, higher resolutions can present a
difficulty—already small icons are much smaller at 1280 × 1024 than at 800 × 600. Try
all of the resolutions to see which you like—just remember that LCD monitors look
sharpest at their native resolution (usually the highest listed).
The color quality is the number of colors displayed on the screen. You can change the
screen resolution with a simple slider, adjusting the color depth from 4-bit all of the way
up to 32-bit color. Unless you have an older video card or a significant video speed issue,
you’ll probably set your system for 32-bit color and never touch this setting again. ch19.indd 863 12/9/09 5:14:44 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 864 Figure 19-60 Settings tab Another option you may see in the Settings tab is dual monitors. Windows supports
the use of two (or more) monitors. These monitors may work together like two halves
of one large monitor, or the second monitor might simply show a duplicate of what’s
happening on the first monitor. Dual monitors are handy if you need lots of screen
space but don’t want to buy a really large, expensive monitor (Figure 19-61). Microsoft
calls this feature DualView. Figure 19-61
My editor hard at
work with dual
monitors ch19.indd 864 12/9/09 5:14:46 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 865 EXAM TIP Windows supports DualView technology, enabling you to use
There are two ways to set up dual monitors: plug in two video cards or use a single
video card that supports two monitors (a “dual-head” video card). Both methods are
quite common and work well. Dual monitors are easy to configure: just plug in the monitors and Windows should detect them. Windows will show both monitors in the Settings
tab, as shown in Figure 19-62. By default, the second monitor is not enabled. To use the
second monitor, just select the Extend the desktop onto this monitor checkbox.
monitors If you need to see more advanced settings, click on…that’s right, the Advanced or Advanced Settings button (Figure 19-63). The title of this dialog box reflects the monitor
and video card. As you can see in the screen shot, this particular monitor is a Samsung
SyncMaster T220 running off of an ATI Radeon 3850 video card.
The two tabs you’re most likely to use are the Adapter and Monitor tabs. The Adapter
tab gives detailed information about the video card, including the amount of video
memory, the graphics processor, and the BIOS information (yup, your video card has a
BIOS, too!). You can also click on the List All Modes button to change the current mode
of the video card, although any mode you may set here, you can also set in the sliders
on the main screen. ch19.indd 865 12/9/09 5:14:46 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 866 Figure 19-63
settings If you’re still using a CRT, you’ll find the Monitor tab a handy place. This is where
you can set the refresh rate (Figure 19-64). Windows only shows refresh rates that the
monitor says it can handle, but many monitors can take a fasterand therefore easier
on the eyesrefresh rate. To see all of the modes the video card can support, uncheck
the Hide modes that this monitor cannot display option.
Monitor tab ch19.indd 866 12/9/09 5:14:47 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 867 NOTE All LCD monitors have a fixed refresh rate If you try this, always increase the refresh rate in small increments. If the screen looks
better, use it. If the screen seems distorted or disappears, wait a moment and Windows
will reset to the original refresh rate. Be careful when using modes that Windows says
the monitor cannot display. Pushing a CRT past its fastest refresh rate for more than a
minute or two can damage it.
Most video cards add their own tab to the Advanced dialog box, such as the one
shown in Figure 19-65. This tab adjusts all of the specialized settings for that video
card. What you see here varies by model of card and version of driver, but here’s a list
of some of the more interesting settings you might see.
video tab Color Correction Sometimes the colors on your monitor are not close enough
for your tastes to the actual color you’re trying to create. In this case you use color correction to fine-tune the colors on the screen to get the look you want.
Rotation All monitors are by default wider than they are tall. This is called landscape mode. Some LCD monitors can be physically rotated to facilitate users who like
to see their desktops taller than they are wide (portrait mode). Figure 19-66 shows the
author’s LCD monitors rotated in portrait mode. If you want to rotate your screen, you
must tell the system you’re rotating it. ch19.indd 867 12/9/09 5:14:47 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 868 Figure 19-66
Portrait mode Modes Most video cards add very advanced settings to enable you to finely tweak
your monitor. These very dangerous settings have names such as “sync polarity” or
“front porch” and are outside the scope of both CompTIA A+ certification and the
needs of all but the most geeky techs. These settings are mostly used to display a nonstandard resolution. Stay out of those settings! Working with Drivers
Now that you know the locations of the primary video tools within the operating system, it’s time to learn about fine-tuning your video. You need to know how to work
with video drivers from within the Display/Personalization applet, including how to
update them, roll back updates, and uninstall them.
Windows is very persnickety when it comes to video card drivers. You can crash
Windows and force a reinstallation simply by installing a new video card and not uninstalling the old card’s drivers. This doesn’t happen every time but certainly can happen. ch19.indd 868 12/9/09 5:14:48 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 869 As a basic rule, always uninstall the old card’s drivers before you install drivers for a
When you update the drivers for a card, you have a choice of uninstalling the outdated drivers and then installing new drivers—which makes the process the same as for
installing a new card—or you can let Windows flex some digital muscle and install the
new ones right over the older drivers.
To update your drivers, go to the Control Panel and double-click the Display applet
or Personalization applet. In the Display Properties/Display Settings dialog box, select
the Settings tab/Monitor tab and click the Advanced or Advanced Settings button. In
the Advanced button dialog box, click the Adapter tab and then click the Properties button. In the Properties dialog box for your adapter (Figure 19-67), select the Driver tab
and then click the Update Driver button to run the Hardware Update wizard. Figure 19-67
Adapter Properties dialog box Practical Application
No other area of the PC world reflects the amazing acceleration of technological improvements more than 3-D graphics—in particular, 3-D gaming—that attempts to create images with the same depth and texture as objects seen in the real world. We are
spectators to an amazing new world where software and hardware race to produce new ch19.indd 869 12/9/09 5:14:49 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 870 levels of realism and complexity displayed on the computer screen. Powered by the wallets of tens of millions of PC gamers always demanding more and better, the video industry constantly introduces new video cards and new software titles that make today’s
games so incredibly realistic and fun. Although the gaming world certainly leads the
PC industry in 3-D technologies, many other PC applications— such as Computer Aided
Design (CAD) programs —quickly snatch up these technologies, making 3-D more useful in many ways other than just games. In this section, we’ll add to the many bits and
pieces of 3-D video encountered over previous chapters in the book and put together
an understanding of the function and configuration of 3-D graphics.
Before the early 1990s, PCs did not mix well with 3-D graphics. Certainly, many 3-D
applications existed, primarily 3-D design programs such as AutoCAD and Intergraph,
but these applications would often run only on expensive, specialized hardware—not
so great for casual users.
The big change took place in 1992 when a small company called id Software created
a new game called Wolfenstein 3D (see Figure 19-68). They launched an entirely new
genre of games, now called first-person shooters (FPSs), in which the player looks out into
a 3-D world, interacting with walls, doors, and other items, and shoots whatever bad
guys the game provides. Figure 19-68 Wolfenstein 3D Wolfenstein 3D shook the PC gaming world to its foundations. That this innovative
format came from an upstart little company made Wolfenstein 3D and id Software
into overnight sensations. Even though their game was demanding on hardware, they ch19.indd 870 12/9/09 5:14:49 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 871 gambled that enough people could run it to make it a success. The gamble paid off for
John Carmack and John Romero, the creators of id Software, making them the fathers
of 3-D gaming.
Early 3-D games used fixed 3-D images called sprites to create the 3-D world. A sprite
is nothing more than a bitmapped graphic such as a BMP file. These early first-person
shooters would calculate the position of an object from the player’s perspective and place
a sprite to represent the object. Any single object had only a fixed number of sprites—if
you walked around an object, you noticed an obvious jerk as the game replaced the current sprite with a new one to represent the new position. Figure 19-69 shows different
sprites for the same bad guy in Wolfenstein 3D. Sprites weren’t pretty, but they
worked without seriously taxing the 486s
Each figure had
and early Pentiums of the time.
a limited number
The second generation of 3-D began
to replace sprites with true 3-D objects,
which are drastically more complex than
sprites. A true 3-D object is composed of a group of points called vertices. Each vertex
has a defined X, Y, and Z position in a 3-D world. Figure 19-70 shows the vertices for
an airplane in a 3-D world. Figure 19-70
a 3-D airplane The computer must track all of the vertices of all of the objects in the 3-D world,
including the ones you cannot currently see. Keep in mind that objects may be motionless in the 3-D world (a wall, for example), may have animation (such as a door opening and closing), or may be moving (like bad monsters trying to spray you with evil
alien goo). This calculation process is called transformation and, as you might imagine,
is extremely taxing to most CPUs. Intel’s SIMD and AMD’s 3DNow! processor extensions were expressly designed to perform transformations.
Once the CPU has determined the positions of all vertices, the system begins to fill
in the 3-D object. The process begins by drawing lines (the 3-D term is edges) between
vertices to build the 3-D object into many triangles. Why triangles? Well, mainly by
consensus of game developers. Any shape works, but triangles make the most sense
from a mathematical standpoint. I could go into more depth here, but that would ch19.indd 871 12/9/09 5:14:50 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 872 require talking about trigonometry, and I’m gambling you’d rather not read that detailed a description! All 3-D games use triangles to connect vertices. The 3-D process
then groups triangles into various shapes called polygons. Figure 19-71 shows the same
model as Figure 19-70, now displaying all of the connected vertices to create a large
number of polygons.
a 3-D airplane Originally, the CPU handled these calculations to create triangles, but now special
3-D video cards do the job, greatly speeding up the process.
The last step in second-generation games was texturing. Every 3-D game stores a
number of image files called textures. The program wraps textures around an object to
give it a surface. Textures work well to provide dramatic detail without using a lot of triangles. A single object may take one texture or many textures, applied to single triangles
or groups of triangles (polygons). Figure 19-72 shows the finished airplane. Figure 19-72
3-D airplane with
textures added True 3-D objects, more often referred to as rendered, immediately created the need
for massively powerful video cards and much wider data buses. Intel’s primary motivation for creating AGP was to provide a big enough pipe for massive data pumping
between the video card and the CPU. Intel gave AGP the ability to read system RAM
to support textures. If it weren’t for 3-D games, AGP (and probably even PCIe) would
almost certainly not exist. ch19.indd 872 12/9/09 5:14:51 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 873 3-D Video Cards
No CPU of the mid-1990s could ever hope to handle the massive processes required
to render 3-D worlds. Keep in mind that to create realistic movement, the 3-D world
must refresh at least 24 times per second. That means that this entire process, from
transformation to texturing, must repeat once every 1/24th of a second! Furthermore,
although the game re-creates each screen, it must also keep score, track the positions
of all of the objects in the game, provide some type of intelligence to the bad guys, and
so on. Something had to happen to take the workload off the CPU. The answer came
from video cards.
Video cards were developed with smart onboard graphics processing units (GPUs). The
GPU helped the CPU by taking over some, and eventually all, of the 3-D rendering duties. These video cards not only have GPUs but also have massive amounts of RAM to
But a problem exists with this setup: How do we talk to these cards? This is done by
means of a device driver, of course, but wouldn’t it be great if we could create standard
commands to speed up the process? The best thing to do would be to create a standardized set of instructions that any 3-D program could send to a video card to do all of the
basic work, such as “make a cone” or “lay texture 237 on the cone you just made.”
The video card instructions standards manifested themselves into a series of application programming interfaces (APIs). In essence, an API is a library of commands that
people who make 3-D games must use in their programs. The program currently using
the video card sends API commands directly to the device driver. Device drivers must
know how to understand the API commands. If you were to picture the graphics system
of your computer as a layer cake, the top layer would be the program making a call to
the video card driver that then directs the graphics hardware.
Several APIs have been developed over the years, with two clear winners among all
of them: OpenGL and DirectX. The OpenGL standard was developed for UNIX systems
but has since been ported, or made compatible with, a wide variety of computer systems, including Windows and Apple computers. As the demand for 3-D video became
increasingly strong, Microsoft decided to throw its hat into the 3-D graphics ring with
its own API, called DirectX. We look at DirectX in depth in the next section.
Although they might accomplish the same task (for instance, translating instructions
and passing them on to the video driver), every API handles things just a little bit differently. In some 3-D games, the OpenGL standard might produce more precise images
with less CPU overhead than the DirectX standard. In general, however, you won’t notice a large difference between the images produced by using OpenGL and DirectX. DirectX and Video Cards
In the old days, many applications communicated directly with much of the PC hardware and, as a result, could crash your computer if not written well enough. Microsoft
tried to fix this problem by placing all hardware under the control of Windows, but
programmers balked because Windows added too much work for the video process
and slowed down everything. For the most demanding programs, such as games, only
direct access of hardware would work. ch19.indd 873 12/9/09 5:14:51 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 874 This need to “get around Windows” motivated Microsoft to unveil a new set of
protocols called DirectX. Programmers use DirectX to take control of certain pieces of
hardware and to talk directly to that hardware; it provides the speed necessary to play
the advanced games so popular today. The primary impetus for DirectX was to build
a series of products to enable Windows to run 3-D games. That’s not to say that you
couldn’t run 3-D games in Windows before DirectX; rather, it’s just that Microsoft wasn’t
involved in the API rat race at the time and wanted to be. Microsoft’s goal in developing
DirectX was to create a 100-percent stable environment, with direct hardware access, for
running 3-D applications and games within Windows.
DirectX is not only for video; it also supports sound, network connections, input
devices, and other parts of your PC. Each of these subsets of DirectX has a name, such
as DirectDraw, Direct3D, or DirectSound.
• DirectDraw Supports direct access to the hardware for 2-D graphics. • Direct3D Supports direct access to the hardware for 3-D graphics—the most
important part of DirectX.
• DirectInput Supports direct access to the hardware for joysticks and other
• DirectSound Supports direct access to the hardware for waveforms.
• DirectMusic Supports direct access to the hardware for MIDI devices.
• DirectShow Supports direct access to network devices for multiplayer games.
Supports direct access to video and presentation devices. Microsoft constantly adds to and tweaks this list. As almost all games need DirectX and
all video cards have drivers to support DirectX, you need to verify that DirectX is installed
and working properly on your system. To do this, use the DirectX Diagnostic Tool. In Windows 2000/XP, you can find it in the System Information program. After you open System
Information (it usually lives in the Accessories | System Tools area of the Start menu), click
the Tools menu and select DirectX Diagnostic Tool (see Figure 19-73).
For Windows Vista/7, go to Start and type dxdiag in the Start text box. Press ENTER to
run the program.
The System tab gives the version of DirectX. The system pictured in Figure 19-73 runs
DirectX 10. You may then test the separate DirectX functions by running through the
other tabs and running the tests.
So, what does DirectX do for video cards? Back in the bad old days before DirectX became popular with the game makers, many GPU makers created their own chip-specific
APIs. 3dfx had Glide, for example, and S3 had ViRGE. This made buying 3-D games
a mess. There would often be multiple versions of the same game for each card. Even
worse, many games never used 3-D acceleration because it was just too much work to
support all of the different cards.
That all changed when Microsoft beefed up DirectX and got more GPU makers to
support it. That in turn enabled the game companies to write games by using DirectX
and have them run on any card out there. The bottom line: When Microsoft comes out ch19.indd 874 12/9/09 5:14:51 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 875 Figure 19-73 The DirectX Diagnostic Tool with a new version of DirectX, all of the GPU companies hurry to support it or they will
be left behind.
Trying to decide what video card to buy gives me the shakes—too many options!
One good way to narrow down your buying decision is to see what GPU is hot at the
moment. I make a point to check out these Web sites whenever I’m getting ready to buy,
so I can see what everyone says is the best.
• www.sharkyextreme.com Troubleshooting Video
People tend to notice when their monitors stop showing the Windows desktop, making video problems a big issue for technicians. Users might temporarily ignore a bad
sound card or other device, but will holler like crazy when the screen doesn’t look the
way they expect. To fix video problems quickly, the best place to start is to divide your
video problems into two groups: video cards/drivers and monitors. ch19.indd 875 12/9/09 5:14:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 876 Troubleshooting Video Cards/Drivers
Video cards rarely go bad, so the vast majority of video card/driver problems are bad or
incompatible drivers or incorrect settings. Always make sure you have the correct driver
installed. If you’re using an incompatible driver, Windows defaults to good old 640 ×
480, 16-color VGA. A driver that is suddenly corrupted usually doesn’t show the problem
until the next reboot. If you reboot a system with a corrupted driver, Windows will do
one of the following: go into VGA mode, blank the monitor, lock up, or display a garbled
screen. Whatever the output, reboot into Safe mode and roll back or delete the driver.
Keep in mind that more advanced video cards tend to show their drivers as installed programs under Add or Remove Programs, so always check there first before you try deleting
a driver by using Device Manager. Download the latest driver and reinstall.
Video cards are pretty durable but they have two components that do go bad: the
fan and the RAM. Lucky for you, if either of these goes out, it tends to show the same
errorbizarre screen outputs followed shortly by a screen lockup. Usually Windows
keeps running; you may see your mouse pointer moving around and windows refreshing, but the screen turns into a huge mess (Figure 19-74). Figure 19-74 Serious video problem ch19.indd 876 12/9/09 5:14:52 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 877 Bad drivers sometimes also make this error, so always first try going into Safe mode
to see if the problem suddenly clears up. If it does, you do not have a problem with the
The last and probably most common problem is nothing more than improperly configured video settings. Identifying the problem is just common senseif your monitor
is showing everything sideways, someone messed with your rotation settings; if your
gorgeous wallpaper of a mountain pass looks like an ugly four-color cartoon, someone
lowered the color depth. Go into your Display Properties and reset them to a setting
that works! The one serious configuration issue is pushing the resolution too high. If
you adjust your resolution and then your monitor displays an error message such as
“Input Signal Out of Range” (Figure 19-75), you need to set your resolution back to
something that works for your video card/monitor combination! Figure 19-75
Pushing a monitor
too hard Troubleshooting Monitors
Because of the inherent dangers of the high-frequency and high-voltage power required
by monitors, and because proper adjustment requires specialized training, this section
concentrates on giving a support person the information necessary to decide whether
a trouble call is warranted. Virtually no monitor manufacturers make schematics of
their monitors available to the public, because of liability issues regarding possible
electrocution. To simplify troubleshooting, look at the process as three separate parts:
common monitor problems, external adjustments, and internal adjustments. ch19.indd 877 12/9/09 5:14:53 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 878 Common Monitor Problems
Although I’m not super comfortable diving into the guts of a monitor, you can fix a
substantial percentage of monitor problems yourself. The following list describes the
most common monitor problems and tells you what to do—even when that means
sending it to someone else.
• Almost all CRT and LCD monitors have replaceable controls. If the Brightness
knob or Menu button stops working or seems loose, check with the manufacturer for replacement controls. They usually come as a complete package.
• For problems with ghosting, streaking, and/or fuzzy vertical edges, check the
cable connections and the cable itself. These problems rarely apply to monitors;
more commonly, they point to the video card.
• If one color is missing, check cables for breaks or bent pins. Check the front
controls for that color. If the color adjustment is already maxed out, the monitor will require internal service.
• As monitors age, they lose brightness. If the brightness control is turned all of
the way up and the picture seems dim, the monitor will require internal adjustment. This is a good argument for power-management functions. Use the power
switch or the power-management options in Windows to turn off the monitor
after a certain amount of time. Common Problems Specific to CRTs
The complexity of CRTs compared to LCDs requires us to look at a number of monitor
problems unique to CRTs. Most of these problems require opening the monitor, so be
careful! When in doubt, take it to a repair shop.
• Most out-of-focus monitors can be fixed. Focus adjustments are usually on the
inside, somewhere close to the flyback transformer. This is the transformer that
provides power to the high-voltage anode.
• Hissing or sparking sounds are often indicative of an insulation rupture on the
flyback transformer. This sound is usually accompanied by the smell of ozone.
If your monitor has these symptoms, it definitely needs a qualified technician.
Having replaced a flyback transformer once myself, I can say it is not worth the
hassle and potential loss of life and limb.
• Big color blotches on the display are an easy and cheap repair. Find the Degauss
button and use it. If your monitor doesn’t have a Degauss button, you can purchase a special tool called a degaussing coil at any electronics store.
• Bird-like chirping sounds occurring at regular intervals usually indicate a problem with the monitor power supply.
• Suppose you got a good deal on a used 19-inch monitor, but the display is kind
of dark, even though you have the brightness turned up all the way. This points
to a dying CRT. So, how about replacing the CRT? Forget it. Even if the monitor ch19.indd 878 12/9/09 5:14:54 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 879 was free, it just isn’t worth it; a replacement tube runs into the hundreds of dollars. Nobody ever sold a monitor because it was too bright and too sharp. Save
your money and buy a new monitor.
• If the monitor displays only a single horizontal or vertical line, the problem is
probably between the main circuit board and the yoke, or a blown yoke coil.
This definitely requires a service call.
• A single white dot on an otherwise black screen means the high-voltage flyback
transformer is most likely shot. Take it into the repair shop. External Adjustments
Monitor adjustments range from the simplest—brightness and contrast—to the more
sophisticated—pincushioning and trapezoidal adjustments. The external controls provide users with the opportunity to fine-tune the monitor’s image. Many monitors have
controls for changing the tint and saturation of color, although plenty of monitors put
those controls inside the monitor. Better monitors enable you to square up the visible
portion of the screen with the monitor housing.
Finally, most monitors have the ability to degauss themselves with the push of a
button. Over time, the shadow mask picks up a weak magnetic charge that interferes
with the focus of the electron beams. This magnetic field makes the image look slightly
fuzzy and streaked. Most monitors have a special built-in circuit called a degaussing coil
to eliminate this magnetic buildup. When the degaussing circuit is used, an alternating current is sent through a coil of wire surrounding the CRT, and this current generates an alternating magnetic field that demagnetizes the shadow mask. You activate
the degaussing coil by using the Degauss button or menu selection on the monitor.
Degaussing usually makes a rather nasty thunk sound and the screen goes crazy for a
moment—don’t worry, that’s normal. Whenever a user calls me with a fuzzy monitor
problem, I always have them degauss first. Troubleshooting CRTs
As shipped, most monitors do not produce an image out to the limits of the screen,
because of poor convergence at the outer display edges. Convergence defines how closely
the three colors can meet at a single point on the display. At the point of convergence,
the three colors combine to form a single white dot. With misconvergence, a noticeable halo of one or more colors appears around the outside of the white point. The
farther away the colors are from the center of the screen, the more likely the chance for
misconvergence. Low-end monitors are especially susceptible to this problem. Even
though adjusting the convergence of a monitor is not difficult, it does require getting
inside the monitor case and having a copy of the schematic, which shows the location
of the variable resistors. For this reason, it is a good idea to leave this adjustment to a
I don’t like opening a CRT monitor. I avoid doing this for two reasons: (1) I know
very little about electronic circuits, and (2) I once almost electrocuted myself. At any
rate, the CompTIA A+ exams expect you to have a passing understanding of adjustments you might need to perform inside a monitor. Before we go any further, let me
remind you about a little issue with CRT monitors (see Figure 19-76). ch19.indd 879 12/9/09 5:14:54 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 880 Figure 19-76
Hey! That’s 25,000
volts! Be careful! The CRT monitor contains a wire called a high-voltage anode, covered with a suction
cup. If you lift that suction cup, you will almost certainly be seriously electrocuted. The
anode wire leads to the flyback transformer and produces up to 25,000 volts. Don’t
worry about what they do; just worry about what they can do to you! That charge is
stored in a capacitor, which holds that charge even if the monitor is turned off. It will
hold the charge even if the monitor is unplugged. That capacitor (depending on the
system) can hold a charge for days, weeks, months, or even years. Knowing this, you
should learn how to discharge a CRT.
Discharging a CRT There are 75,000 opinions on how to discharge a CRT properly.
Although my procedure may not follow the steps outlined in someone’s official handbook
on electrical code, I know this works. Read the rules, and then look at Figure 19-77. Figure 19-77
CRT High-voltage anode 1. Make sure everything is unplugged.
2. If possible, let the monitor sit for a couple of hours. Most good monitors
discharge themselves in two to three hours, and many new monitors discharge
in just a few moments.
3. Get a heavy, well-insulated, flat-head screwdriver.
4. Get a heavy-gauge wire with alligator clips on each end.
5. Do not let yourself be grounded in any way. Wear rubber-soled shoes, and no
rings or watches. ch19.indd 880 12/9/09 5:14:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 881 6. Wear safety goggles to protect yourself in the very rare case that the CRT implodes.
7. Remove the monitor’s case. Remember where the screw went in.
8. Attach one alligator clip to an unpainted part of the metal frame of the monitor.
9. Clip the other clip to the metal shaft of the screwdriver.
10. Slide the screwdriver blade under the suction cup. Make triple-sure that neither
you nor the screwdriver is in any incidental contact with anything metal.
11. Slide the blade under until you hear a loud pop—you’ll also see a nice blue flash.
12. If anyone is in the building, they will hear the pop and come running. Tell them
13. Wait about 15 minutes and repeat.
The main controls that require you to remove the monitor case to make adjustments
include those for convergence, gain for each of the color guns, and sometimes the focus
control. A technician with either informal or formal training in component-level repair
can usually figure out which controls do what. In some cases, you can also readily spot
and repair bad solder connections inside the monitor case, and thus fix a dead or dying
CRT. Still, balance the cost of repairing the monitor against the cost of death or serious
injury—is it worth it? Finally, before making adjustments to the display image, especially with the internal controls, give the monitor at least 15 to 30 minutes of warm-up
time. This is necessary both for the components on the printed circuit boards and for
the CRT itself. Troubleshooting LCDs
With the proliferation of LCD panels in the computing world, PC techs need to have
some understanding of what to do when they break. Some of the components you can
fix, including replacing some of the internal components. I tend to use monitor repair
shops for most LCD issues, but let’s take a look.
An LCD monitor may have bad pixels. A bad pixel is any single pixel that does not react the way it should. A pixel that never lights up is a dead pixel, a pixel that is stuck on
pure white is a lit pixel, and a pixel on a certain color is a stuck pixel. You cannot repair
bad pixels; the panel must be replaced. All LCD panel makers allow a certain number
of bad pixels, even on a brand-new LCD monitor! You need to check the warranty for
your monitor and see how many they allow before you may return the monitor.
• If your LCD monitor cracks, it is not repairable and must be replaced.
• If the LCD goes dark but you can still barely see the image under bright lights,
you lost either the lamp or the inverter. In many cases, especially with superthin panels, you’ll replace the entire panel and lamp as a unit. On the other
hand, an inverter can be on a separate circuit board that you can replace, such
as the one pictured in Figure 19-78.
• If your LCD makes a distinct hissing noise, an inverter is about to fail. Again,
you can replace the inverter if need be. ch19.indd 881 12/9/09 5:14:55 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 882 Figure 19-78
labeled CCFL backlight Main board/logic Power supply/inverters Timing control Be careful if you open an LCD to work on the inside. The inverter can bite you in
several ways. First, it’s powered by a high-voltage electrical circuit that can give you a
nasty shock. Worse, the inverter will retain a charge for a few minutes after you unplug
it, so unplug and wait for a bit. Second, inverters get very hot and present a very real
danger of burning you at a touch. Again, wait for a while after you unplug it to try to
replace. Finally, if you shock an inverter, you might irreparably damage it. So use proper
Bottom line on fixing LCD monitors? You can find companies that sell replacement
parts for LCDs, but repairing an LCD is difficult, and there are folks who will do it for
you faster and cheaper than you can. Search for a specialty LCD repair company. Hundreds of these companies exist all over the world. Cleaning Monitors
Cleaning monitors is easy. Always use antistatic monitor wipes or at least a general antistatic cloth. Some LCD monitors may require special cleaning equipment. Never use
window cleaners that contain ammonia or any liquid because getting liquid into the
monitor may create a shocking experience! Many commercial cleaning solutions will
also melt older LCD screens, which is never a good thing. Beyond A+
Video and CMOS
I’m always impressed by the number of video options provided in CMOS, especially
in some of the more advanced CMOS options. I’m equally impressed by the amount
of disinformation provided on these settings. In this section, I’ll touch on some of the
most common CMOS settings that deal with video. You may notice that no powermanagement video options have been included. ch19.indd 882 12/9/09 5:14:56 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 883 Video
Every standard CMOS setup shows an option for video support. The default setting is
invariably EGA/VGA. Many years ago, this setting told the BIOS what type of card was
installed on the system, enabling it to know how to talk to that card. Today, this setting has no meaning. No matter what you put there, the system will ignore it and boot
normally. Init Display First
This CMOS setting usually resides in an advanced options or BIOS options screen. In
multi-monitor systems, Init Display First enables you to decide between PCIe and PCI
as to which monitor initializes at boot. This also determines the initial primary monitor for Windows. Assign IRQ for VGA
Many video cards do not need an interrupt request (IRQ). This option gives you the ability to choose whether your video card gets an IRQ. In general, lower-end cards that do
not provide input to the system do not need an IRQ. Most advanced cards will need
one; try it both ways. If you need it, your system will freeze up without an IRQ assigned.
If you don’t need it, you get an extra IRQ. VGA Palette Snoop
True-VGA devices only show 16 out of a possible 262,000 colors at a time. The 16 current colors are called the palette. VGA Palette Snoop opens a video card’s palette to other
devices that may need to read or temporarily change the palette. I am unaware of any
device made today that still needs this option. Video Shadowing Enabled
As mentioned in previous chapters, this setting enables you to shadow the Video ROM.
In most cases, this option is ignored as today’s video cards perform their own automatic
shadowing. A few cards require this setting to be off, so I generally leave it off now, after
years of leaving it on. Other Display Technologies
A few other screen technologies exist, but not so much for computer monitors. Plasma
and DLP screens grace many a household’s media room as the primary television display. Plasma
Plasma display panels (PDP) are a very popular technology for displaying movies. Unfortunately, plasma TVs have two issues that make them a bad choice for PC use. First, they
have strange native resolutions (such as 1366 × 768) that are hard to get your video
card to accept. Second is burn-inthe tendency for a screen to “ghost” an image even
after the image is off the screen. Plasma TV makers have virtually eliminated burn-in,
but even the latest plasma displays are subject to burn-in when used with PC displays. ch19.indd 883 12/9/09 5:14:56 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 884 DLP
Digital Light Processing (DLP) displays use a chip covered in microscopically small mirrors (Figure 19-79). Figure 19-79
DLP chip (photo
courtesy of Texas
Instruments) These individual mirrors move thousands of times per second toward and away from
a light source. The more times per second they move toward a light source, the whiter
the image; the fewer times they move, the grayer the image. See Figure 19-80 for a diagram of how the mirrors would appear in a microscopic close-up of the chip. Figure 19-80 Microscopic close-up of DLP showing tiny mirrors—note that some are tilted. Figure 19-81 shows a diagram of a typical DLP system. The lamp projects through
a color wheel onto the DLP chip. The DLP chip creates the image by moving the tiny
mirrors, which in turn reflect onto the screen. ch19.indd 884 12/9/09 5:14:57 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 885 Figure 19-81 DLP in action DLP was very popular for a time in home theater systems, as it makes an amazingly
rich image. DLP has had very little impact on PC monitors, but has had great success
as projectors. DLP projectors are much more expensive than LCD projectors, but many
customers feel the extra expense is worth the image quality. Chapter Review Questions
1. What do we call the time it takes to draw the entire screen and get the electron
guns back to the upper-left corner?
A. Horizontal refresh rate
B. Horizontal redraw rate
C. Vertical refresh rate
D. Vertical redraw rate
2. What does the dot pitch signify about a CRT monitor?
A. The resolution, such as 1024 × 768
B. The sharpness of the picture, such as 0.31 or 0.18
C. The maximum refresh rate, such as 100 Hz
D. The minimum refresh rate, such as 60 Hz ch19.indd 885 12/9/09 5:14:58 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19 CompTIA A+Certification All-in-One Exam Guide 886 3. On an LCD monitor, what is the technology that uses a matrix of wires under
A. Active matrix
B. Passive matrix
C. Active TFT
D. Passive TFT
4. What provides the illumination for LCD monitors?
D. LCD panel
5. Which statement best describes the difference, if any, between CRT and LCD
A. The CRT has a single native resolution; LCDs have no native resolution.
B. The CRT has three native resolutions; LCDs have no native resolution.
C. The CRT has no native resolution; LCDs have three native resolutions.
D. The CRT has no native resolution; LCDs have a single native resolution.
6. Which typically uses more wattage?
7. What is WSXGA+ resolution?
A. 1024 × 768
B. 1280 × 1024
C. 1680 × 1050
D. 1920 × 1080
8. What is the processor on a video card called?
D. MPU ch19.indd 886 12/9/09 5:14:59 PM All-In-One / CompTIA Network+ All-in-One Exam Guide / Meyers & Jernigan / 170133-8 / Chapter 19
All-In-One Chapter 19: Video 887 9. What Microsoft API supports 3-D graphics?
A. Active Desktop
10. How would you adjust your screen settings in Windows Vista?
A. Go to Start | Run and type DISPLAY to open the Display applet.
B. Go to Start | Control Panel and double-click the Personalization applet
C. Go to Start | Control Panel and double-click the Display applet icon.
D. Go to Start | All Programs and select the Display applet icon. Answers
1. C. The amount of time it takes to draw the entire screen and get the electron
guns back to the upper-left corner is called the vertical refresh rate.
2. B. The dot pitch, measured in millimeters, tells you how fine the screen will be.
3. B. Passive matrix technology uses a matrix of wires under colored glass.
4. A. The backlights provide the illumination for the LCD panel.
5. D. The CRT has no native resolution; LCDs have a single native resolution.
6. A. CRTs use a lot more wattage than LCDs.
7. C. WSXGA+ resolution is 1680 × 1050.
8. B. You’ll typically see video card processors referred to as GPUs.
9. B. Microsoft makes the DirectX API to support 3-D programs.
10. B. The Personalization applet in Control Panel enables you to change video
settings in Windows Vista. ch19.indd 887 12/9/09 5:14:59 PM ...
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This note was uploaded on 04/27/2010 for the course COMPTIA 1201 taught by Professor N/a during the Spring '10 term at Galveston College.
- Spring '10