Video Chapter 17 © 2007 The McGraw-Hill Companies, Inc. All rights reserved Overview • In this chapter, you will learn to – Explain how video displays work – Select the proper video card – Install and configure video software – Troubleshoot basic video problems © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video • Video consists of two devices—the video card (display adapter) and the monitor • The video card consists of two distinct components – One takes commands from the computer and updates its own onboard RAM – The other scans the RAM and sends data to the monitor Monitor © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video card CRT Monitors © 2007 The McGraw-Hill Companies, Inc. All rights reserved CRT • All CRT monitors have a cathode ray tube (CRT), which is a vacuum tube • One end of this tube is a slender cylinder that consists of three electron guns • The wide end of the CRT is the display screen © 2007 The McGraw-Hill Companies, Inc. All rights reserved CRT • When power is applied to the electron guns, a stream of electrons is generated • This stream is subjected to a magnetic field generated by a ring of electromagnets called a yoke • The phosphor coating releases energy as visible light when struck by the electrons – Phosphors continue to glow momentarily after being struck—called persistence © 2007 The McGraw-Hill Companies, Inc. All rights reserved Essentials CompTIA A+ Essentials CRT Refresh Rates © 2007 The McGraw-Hill Companies, Inc. All rights reserved CRT Refresh Rates Video data is displayed on the monitor as the electron gun sweeps the display horizontally, energizing appropriate areas on the phosphor coating. • Horizontal refresh rate (HRR) – The speed at which the electron beam moves across the screen © 2007 The McGraw-Hill Companies, Inc. All rights reserved • Vertical refresh rate (VRR) – The amount of time taken by the monitor to draw the entire screen and get the electron beam back to the start CRT Refresh Rates • Video cards push the monitor at a given VRR, and then the monitor determines the HRR – If the VRR is set too low, you’ll see flicker – If it is set too high, you’ll have a distorted screen image and may damage the monitor • Multisync (multiple-frequency monitor) monitors support multiple VRRs © 2007 The McGraw-Hill Companies, Inc. All rights reserved Phosphors • Phosphors and shadow mask – Phosphors are dots inside the CRT monitor that glow red, green, or blue when an electron gun sweeps over them – Phosphors are evenly distributed across the front of the monitor © 2007 The McGraw-Hill Companies, Inc. All rights reserved One group of red, green, and blue phosphors is called a triad Shadow Mask • Shadow mask is a screen that enables the proper electron gun to light the proper phosphor • Electron guns sweep across the phosphors as a group • The area of phosphors lit at one time by a group of guns is called a picture element, or pixel © 2007 The McGraw-Hill Companies, Inc. All rights reserved Resolution • Monitor resolution is always shown as the number of horizontal pixels times the number of vertical pixels • Some common resolutions are 640 x 480, 800 x 600, 1024 x 768, 1280 x 1024, and 1600 x 1200 • These resolutions match a 4:3 ratio called the aspect ratio © 2007 The McGraw-Hill Companies, Inc. All rights reserved Dot Pitch • Dot pitch—diagonal distance between phosphorous dots of the same color – Range from 0.39 mm to as low as 0.18 mm – The lower the dot pitch, the more dots across the screen, which produces a sharper, more defined image © 2007 The McGraw-Hill Companies, Inc. All rights reserved Bandwidth • Bandwidth—number of times an electron gun can be turned on or off per second – Bandwidth is measured in megahertz (MHz) – VRR determined by bandwidth and resolution Bandwidth pixels per page = Maximum VRR For example, a 17-inch monitor with a 100MHz bandwidth and a resolution of 1024 x 768 can support a maximum VRR of 127 Hz 100,000,000 (1024 x 768) = 127 Hz © 2007 The McGraw-Hill Companies, Inc. All rights reserved LCD Monitors • Liquid crystal displays – Thinner and lighter – Much less power – Flicker free – Don’t emit radiation – Called flat panels or flat panel displays © 2007 The McGraw-Hill Companies, Inc. All rights reserved How LCDs Work • Liquid crystals take advantage of the property of polarization • Liquid crystals are composed of specially formulated liquid – Liquid is full of long, thin crystals that always orient themselves in the same direction • The crystals act exactly like a liquid polarized filter © 2007 The McGraw-Hill Companies, Inc. All rights reserved Liquid Crystal Molecules • LCD monitors use liquid crystal molecules that tend to line up together – These molecules take advantage of polarization – Fine grooves in a piece of glass will cause the molecules to line up along the grooves © 2007 The McGraw-Hill Companies, Inc. All rights reserved Twisting Molecules • Use two pieces of glass with fine grooves oriented at a 90° angle – Molecules in the middle will try to line up to both sides—creating a nice twist © 2007 The McGraw-Hill Companies, Inc. All rights reserved Add Polarizing Filters • Now add polarizing filters to both sides – The liquid crystal will twist the light and enable it to pass through – Adding an electrical potential will cause the crystals to try to align to the electrical field • To darken an area, apply a charge © 2007 The McGraw-Hill Companies, Inc. All rights reserved Passive Matrix • Uses three matrices to produce color • Above the intersections of the wires, glass covers tiny red, green, & blue dots • Slow and tends to create an overlap between pixels • Slightly blurred effect © 2007 The McGraw-Hill Companies, Inc. All rights reserved Dual-Scan Passive Matrix • Refreshes two lines at a time • Still used on some low-end LCD panels • Largely replaced with TFT – Thin film transistor © 2007 The McGraw-Hill Companies, Inc. All rights reserved Thin Film Transistor (TFT) • Thin film transistor (TFT) is also known as active matrix • It uses one or more tiny transistors to control each color dot • Brighter, with better contrast • Can handle a variety of colors, and has a much wider viewing area © 2007 The McGraw-Hill Companies, Inc. All rights reserved LCD Components • Backlights illuminate the image – Inverters power the backlights (with AC) • LCD logic board uses DC • Cold cathode fluorescent lamp (CCFL) used in backlights © 2007 The McGraw-Hill Companies, Inc. All rights reserved LCD Resolution • All LCD monitors have a native resolution – Display sharpest picture when set to this resolution • LCD panels cannot display more than their pixel limitation • When set to lower resolutions, image quality is severely degraded © 2007 The McGraw-Hill Companies, Inc. All rights reserved LCD Components • Brightness – Determined by backlight – Measured in nits (100 to 1000 with the avg. at 300) • Response rate – Similar concept as refresh rate – Lower rate (6–8 ns) better – Low-end LCDs (20–25 ns) have ghosting problems • Contrast ratio – Difference between lightest and darkest – Low end (250:1) to high end (1000:1) © 2007 The McGraw-Hill Companies, Inc. All rights reserved Projectors • Front-view and rear-view – CRT projectors used first and are expensive – LCD projectors light and comparatively inexpensive – Today, almost all portable projectors are LCDs © 2007 The McGraw-Hill Companies, Inc. All rights reserved Projector Features • Lumens – Amount of light provided by a light source – Higher lumens = brighter picture • Throw – Size of an image at a certain distance – Related to aspect ratio • Lamps – Get very hot – Expensive—typically a few hundred dollars © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Features • Overview – Size – Connections – Adjustments © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Features—Size • CRT monitors measured in inches • Monitor size (not viewable area) • Viewable image size (VIS)—screen size from diagonal corners • LCD monitors use just the VIS value Monitor size © 2007 The McGraw-Hill Companies, Inc. All rights reserved VIS Common Features—Connections • Traditional CRT monitors use a 15-pin, 3-row, DB-type connector and a power plug • LCDs can use DB-15 or digital video interface (DVI) – DVI-D (digital) – DVI-A (analog) – DVI A/D or DVI-I (interchangeable) DVI to VGA Adapter © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Features—Connections • The Random Access Memory Digital-toAnalog Converter (RAMDAC) chip – Converts digital signals into analog signals for analog CRTs • LCD monitors use digital signals – Circuitry for converting analog signals to digital usually on board the LCD monitors – When using the DVI connection, not translated to analog (RAMDAC not used) – Digital from video card sent and used as digital on LCD monitor © 2007 The McGraw-Hill Companies, Inc. All rights reserved RAMDAC © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Features—Adjustments • Controls – On/off button – Brightness/contrast button – Onboard menu system • Two main functions of menu – Physical screen adjustments – Color adjustments © 2007 The McGraw-Hill Companies, Inc. All rights reserved Power Conservation • About half the power required by the PC is consumed by the CRT monitor – Monitors that meet the VESA specs can reduce power consumption by +/–75 percent – Done with Display Power-Management Signaling (DPMS) • CRT monitor consumes +/–120 watts – Power-down DPMS mode reduces to +/–25 watts – Full shutoff DPMS mode reduces to +/–15 watts – Takes about 15–30 seconds to restore display © 2007 The McGraw-Hill Companies, Inc. All rights reserved Power Conservation • LCD monitor uses less than half the electricity as a CRT • 19-inch 4:3 flat panel display uses +/– 33 watts at peak usage – Less than 2 watts in DPMS mode – Replacing CRTs with LCDs can have an impact on the electric bill © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Cards © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Card • Two major components 1. Video RAM – Stores the video image 2. Video processor circuitry – Takes information from video RAM and sends it to the monitor © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video RAM • Text video cards display only the 256 ASCII characters – Older systems displayed on 80 chars/row and only 24 rows—only 1920 bytes of RAM needed • Graphics video cards could turn any pixel on or off – Resolution of 320 x 200 pixels required 8 KB – To add color, multiple bits added • 8 bits = 256 colors • 24 bits = 16.7 million colors (true color) • Color depth is represented as bits (color depth of 24 bits) and not the number of colors © 2007 The McGraw-Hill Companies, Inc. All rights reserved Color Depth • Color depth is represented as bits – “Color depth of 24 bits” – Not the number of colors – 24 bits commonly referred to as “true color” Number of Colors 2 colors 4 colors 256 colors 64,000 colors 16.7 million colors 16.7 million colors 8-bit opacity Number of Bits 1 bit (mono) 2 bits 8 bits 16 bits 24 bits 32 bits © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Modes • VGA (640 x 480) • Beyond VGA – SVGA, XGA, and more Mode QVGA WVGA SVGA XGA WXGA HDTV 720 SXGA Resolution 320 x 240 800 x 480 800 x 600 1024 x 768 1200 x 800 1280 x 720 1280 x 1024 Mode WSXGA SXGA+ WSXGA+ UXGA HDTV 1080 WUXGA WQUXGA © 2007 The McGraw-Hill Companies, Inc. All rights reserved Resolution 1440 x 900 1400 x 1050 1680 x 1050 1600 x 1200 1920 x 1080 1920 x 1200 2560 x 1600 Motherboard Connection • PCI slots – 800 x 600 with refresh of 70 Hz at 8 bits (256 colors) requires 33.6 Mbps bandwidth – 24 bits (16.7 million colors) requires 100.8 Mbps – Not enough bandwidth available on shared PCI bus • AGP (accelerated graphics port) – Dedicated to video – Several advantages over PCI © 2007 The McGraw-Hill Companies, Inc. All rights reserved AGP Benefits • AGP is a single special port dedicated to video – Derived from the 66-MHz, 32-bit PCI 2.1 specification – Strobing increases signals two, four, and eight times for each clock cycle – Uses its own dedicated data bus connected to Northbridge – Supports pipelining – Uses sidebanding (can send and receive at same time) – Can “steal” chunks of regular system memory © 2007 The McGraw-Hill Companies, Inc. All rights reserved PCIe (PCI Express) • • • • Developed to be replacement for PCI Designed to replace AGP also Incredibly fast serial communications Supports many of the AGP benefits – Sidebanding – System memory access PCIe card © 2007 The McGraw-Hill Companies, Inc. All rights reserved Graphics Processor • The most important decision in buying a video card is the graphics processor • Most video processors are made by – NVIDIA – ATI • ATI Radeon X1950 XTX 512 MB – ATI – Radeon X1950 XTX – 512 MB © 2007 The McGraw-Hill Companies, Inc. All rights reserved Manufacturer Processor & Model No. Amount of RAM Graphics Processor • NVIDIA and ATI release multiple models of graphics processors each year • Most features only seen in 3-D games – – – – – Textures Transparency Shadows Reflection Bump mapping © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Memory • Video RAM constantly updates to reflect every change that takes place on screen • Three bottlenecks – Data throughput speed – Access speed – Simple capacity • Overcome bottlenecks in three ways – Wider bus between video RAM and video processor – Specialized super-fast RAM – More RAM © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Memory • Bus widths – 64, 128, and even 256 bits wide • Most of the graphics rendering and processing is handled on the card – Dedicated video processor rather than the CPU © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Memory • Video RAM Technologies Acronym VRAM WRAM SGRAM DDR SDRAM DDR2 SDRAM GDDR3 SDRAM GDDR4 SDRAM Name Video RAM Windows RAM Synchronous Graphics RAM Double Data Rate SDRAM DDR Version 2 Graphics DDR V. 3 Graphics DDR V. 4 © 2007 The McGraw-Hill Companies, Inc. All rights reserved Purpose Original Never caught on Special SDRAM Used on budget graphics cards Replaced with GDDR3 Faster DDR2 Upgrade of GDDR3 Installing and Configuring Video Software © 2007 The McGraw-Hill Companies, Inc. All rights reserved Physical Installation Issues • Two primary issues 1. Long cards • Some video cards are tall and may not fit in all cases • Get a new case or new video card 2. Proximity to nearest PCI card – Video cards run very hot – Leave space for ventilation – Good practice is to leave the slot next to an AGP card empty to allow better airflow © 2007 The McGraw-Hill Companies, Inc. All rights reserved Software • Two-step process 1. Load the drivers – Install from CD or use built-in driver (if you must) – Built-in driver likely the oldest – Check the manufacturer’s Web site for updates 2. Check the drivers • Use the Display applet © 2007 The McGraw-Hill Companies, Inc. All rights reserved Display Applet • Found in Control Panel or right-click the desktop and choose Properties • Making the screen pretty – Themes – Desktop – Appearance – Other tabs – Screen Saver – Settings © 2007 The McGraw-Hill Companies, Inc. All rights reserved Display Applet • Screen Saver – Power Management features – Covered in Chapter 19 © 2007 The McGraw-Hill Companies, Inc. All rights reserved Display Applet • Settings tab – Allows you to configure multiple monitors – Can configure resolution and color depth © 2007 The McGraw-Hill Companies, Inc. All rights reserved Display Applet—Advanced • Monitor tab – Can update monitor driver – Can set the screen refresh rate • Change in small increments • Can cause damage © 2007 The McGraw-Hill Companies, Inc. All rights reserved Display Applet—Advanced • Many video cards have card-specific tab – Color Correction • Can adjust screen colors – Rotation • Portrait or Landscape – Modes • Very advanced settings • Usually not needed © 2007 The McGraw-Hill Companies, Inc. All rights reserved Working with Drivers • Video drivers work same way as other hardware drivers – Can access this screen from Device Manager or Device applet – Update driver – Roll back driver – Uninstall driver – As a basic rule • Uninstall old drivers before installing drivers for new video card © 2007 The McGraw-Hill Companies, Inc. All rights reserved IT Technician CompTIA A+ Technician 3-D Graphics © 2007 The McGraw-Hill Companies, Inc. All rights reserved 3-D Graphics • Improvements driven by games – Although improvements used in other applications such as computer aided design (CAD) – First-person shooters (FPSs) such as Wolfenstein 3D and Doom started move to 3-D © 2007 The McGraw-Hill Companies, Inc. All rights reserved Transformation and Sprites • Movement of 3-D objects referred to as transformation (CPU intensive) – Intel’s SIMD and AMD’s 3DNow! expressly designed to perform transformation – Early 3-D games used sprites • Just a bitmap graphic moved around on the screen • Each figure had a limited number of sprites or angles of view © 2007 The McGraw-Hill Companies, Inc. All rights reserved 3-D Objects • The second generation produced 3-D objects thru a process called rendering – – – – Composed of a group of points or vertices Vertices were connected with lines (called edges) The edges form triangles that create polygons The last step is adding a texture (or skin) © 2007 The McGraw-Hill Companies, Inc. All rights reserved 3-D Video Cards • Graphics processing units needed – Screens redrawn at least 24 times per second – 3-D video cards have massive amounts of RAM for textures and fast processors for transformations – Application programming interfaces (APIs) created to talk to hardware directly • OpenGL ported from UNIX • DirectX (Microsoft only) © 2007 The McGraw-Hill Companies, Inc. All rights reserved DirectX and Video Cards • DirectX provides direct access to hardware as follows: – – – – – – – DirectDraw: for 2-D graphics Direct3D: for 3-D graphics DirectInput: for joysticks and game controllers DirectSound: for waveforms DirectMusic: for MIDI devices DirectPlay: for multiplayer games DirectShow: for video and presentation devices © 2007 The McGraw-Hill Companies, Inc. All rights reserved DirectX Diagnostic Tool • Accessories | System Tools | System Information – Tools | DirectX Diagnostic Tool • Or…Run DXDiag © 2007 The McGraw-Hill Companies, Inc. All rights reserved Web sites • Some useful Web sites to visit before making a hardware-buying decision – – – – www.arstechnica.com www.hardocp.com www.tomshardware.com www.sharkyextreme.com © 2007 The McGraw-Hill Companies, Inc. All rights reserved Troubleshooting Video © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Card Problems • Vast majority of problems are – Improper or corrupt drivers – Incorrect settings • Incompatible or corrupt driver symptoms – 640 x 480 mode – 16-color VGA • Your response – Boot into safe mode and remove driver – Use Add/Remove programs if available – Use Device Manager © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Card HW Problems • Hardware problems usually just one of two – Fan has gone out – RAM is faulty • Faulty hardware symptoms – Bizarre output – May see mouse moving – Display is a mess © 2007 The McGraw-Hill Companies, Inc. All rights reserved Video Card Problems • Don’t forget the obvious – If everything is sideways, check the rotation settings – Limited colors—check the color depth – Resolution set too high • “Input signal out of range” © 2007 The McGraw-Hill Companies, Inc. All rights reserved Troubleshooting Monitors Opening up a monitor can be deadly Even when the power is disconnected, certain components inside a monitor retain a substantial voltage for an extended period of time. If you accidentally short one of the components, it could actually kill you! © 2007 The McGraw-Hill Companies, Inc. All rights reserved Troubleshooting Monitors • Dangerous inside a monitor • Proper adjustment requires specialized training • Your goal is to determine if a problem is in one these three categories: – Common monitor problems – External adjustments – Internal adjustments © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Monitor Problems • Control buttons are replaceable – Check with the manufacturer • Ghosting, streaking, fuzzy vertical edges – Check the cable connections and cable itself • Missing color – Check cable for breaks, bent pins, and monitor adjustments • Loss of brightness – Normal with age, so use power management – Internal adjustments may be made © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Problems—CRTs • You may be able to fix this – Big color blotches—degauss it with degauss button • It’s probably beyond fixing – Dim display (with brightness turned up) • Take it in to a repair shop – Out of focus—adjustment near the flyback transformer – Hissing or sparking sounds – Bird-like chirping sounds – Single horizontal or vertical line – Single white dot on a black screen © 2007 The McGraw-Hill Companies, Inc. All rights reserved Troubleshooting Monitors • External controls provide users with the opportunity to fine-tune the monitor’s image – Brightness and contrast – Pincushioning – Trapezoidal adjustments – Tint and saturation of color – Monitors have a built-in circuit called a degaussing coil • Eliminates magnetic build-up • A fuzzy looking monitor may be fixed by degaussing it • Disregard the loud “thunk” sound—it’s normal © 2007 The McGraw-Hill Companies, Inc. All rights reserved Troubleshooting CRTs • Convergence defines how closely the three colors will combine • Misconvergence causes halos – Most likely near the edges of the screen – Can be set by internal adjustments – Schematics of monitor will show location of variable resistor that can be adjusted • Manufacturers won’t give you the schematics • Leave to a trained specialist © 2007 The McGraw-Hill Companies, Inc. All rights reserved High-Voltage Anode Lifting this suction cup will almost certainly kill you! High-voltage anode © 2007 The McGraw-Hill Companies, Inc. All rights reserved • Under the suction cup is the actual highvoltage anode • The wire leading from the suction cup goes to the flyback transformer • There’s a big capacitor that can hold up to 25,000 volts of charge for days, weeks, months, or even years Discharging a CRT Do NOT attempt to discharge a monitor unless properly trained and equipped © 2007 The McGraw-Hill Companies, Inc. All rights reserved Common Problems—LCDs • Symptoms – Cracked LCD monitors: not repairable – LCD goes dark: lost either lamp or inverter – Hissing noise: inverter is about to fail • LCD repair companies – Specialize in repairing LCD monitors • Bad pixels – – – – Normal to have some bad pixels Dead pixel: never lights up Lit pixel: stays on pure white Stuck pixel: stays on certain color © 2007 The McGraw-Hill Companies, Inc. All rights reserved Cleaning Monitors • Anti-static monitor wipes or anti-static cloths should be used for cleaning the monitor – Do not use window cleaners – Avoid commercial cleaning solutions on LCD screens © 2007 The McGraw-Hill Companies, Inc. All rights reserved Beyond A+ • Video setting for EGA/VGA – Has no meaning today and is ignored • Init Display First – Determines which monitor to boot first in a multimonitor system • Assign IRQ for VGA – Not needed for low-end cards – High end: Try it each way • VGA Palette Snoop – Not used today • Video Shadowing Enabled – Typically ignored but sometimes required to be off © 2007 The McGraw-Hill Companies, Inc. All rights reserved SLI and Crossfire • Splitting the processing load between two or more GPUs – NVIDIA calls theirs Scalable Link Interface (SLI) – ATI calls theirs CrossFire • Two video cards installed and connected with a bridge card © 2007 The McGraw-Hill Companies, Inc. All rights reserved TV and PCs • TV Out connects computer to TV • Tuner cards – Allows PC to mimic some features of Tivo • HDMI (High Definition Multimedia Interface) – Designed to replace DVI connections © 2007 The McGraw-Hill Companies, Inc. All rights reserved TV and PCs • Plasma – Not suited for PCs • Odd native resolutions (such as 1366x768) • Burn-in—tendency for a screen to ghost an image • DLP – Digital light processing • SED, FED – Combines CRT strengths with LCD strengths – Surface-conduction electron emitter display – Field emission display © 2007 The McGraw-Hill Companies, Inc. All rights reserved © 2007 The McGraw-Hill Companies, Inc. All rights reserved