Video Video Chapter 21
Overview 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
Video Video = hardware and software interacting to create a picture. The monitor displays the image. The video card handles communication between the CPU and monitor. The OS needs drivers so it can facilitate this communication. Applications need to be set up properly to work with video. Figure 1: Typical monitor and video card
CRT Monitors CRT Monitors
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.
CRT (continued) Power applied to the electron guns generates a stream of electrons. 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 this is called persistence.
CRT (continued) Figure 2: Electron stream in the CRT
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 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 (continued) Figure 3: Electron guns sweep from left to right.
CRT Refresh Rates (continued) Figure 4: Horizontal refresh rate
CRT Refresh Rates (continued) Figure 5: Vertical refresh rate
CRT Refresh Rates (continued) 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. Typical VRRs: 60, 72, 75, 85, 100 Hertz (Hz) Multisync monitors (multiple-frequency monitors) support multiple VRRs.
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.
Shadow Mask The 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.
Shadow Mask (continued) Figure 6: A monitor is a grid of red, green, and blue phosphors.
Shadow Mask (continued) Figure 7: Shadow mask
Resolution CRTs change resolution by changing the size of the electron gun s beam. The wider the beam, the lower the resolution. Figure 8: Resolution versus pixel size
Resolution (continued) Monitor resolution is always shown as the number of horizontal pixels times the number of vertical pixels. Some common resolutions: 640 480 800 600 1024 768 1280 960 1600 1200 These resolutions match a 4:3 ratio called the aspect ratio.
Resolution (continued) Figure 9: One triad
Lab Adjust Resolution Get into the Display applet or Personalization applet. Find the resolution slider. Switch resolution to the these settings (if possible): VGA: 640 480 SVGA: 800 600 XGA: 1024 768 SXGA: 1280 1024
Lab Can You Buy a CRT? Go to one of the following Web sites: www.newegg.com www.bestbuy.com www.tigerdirect.com www.amamax.com www.cdw.com Locate the most expensive and least expensive CRTs. Can you find a CRT at all?
LCD Monitors Liquid crystal displays Thinner and lighter Much less power Flicker-free Don t emit radiation Called flat panels or flat panel displays Three types in use Passive matrix Dual-scan passive matrix Thin film transistor (active matrix)
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.
How LCDs Work (continued) Figure 10: Waves of similar orientation
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. Figure 11: Liquid crystal molecules tend to line up together.
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.
Liquid Crystal Molecules (continued) Figure 12: Liquid crystal molecules twisting
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.
Add Polarizing Filters (continued) Figure 13: No charge, enabling light to pass
Add Polarizing Filters (continued) Figure 14: Electrical charge, no light is able to pass
Passive Matrix Uses three matrices to produce color Above the intersections of the wires, glass covers tiny red, green, and blue dots Slow and tends to create an overlap between pixels Slightly blurred effect
Passive Matrix (continued) Figure 15: LCD pixels
Passive Matrix (continued) Figure 16: Single character for static LCD numeric display
Passive Matrix (continued) Figure 17: An LCD matrix of wires
Passive Matrix (continued) Figure 18: Passive matrix display
Dual-Scan Passive Matrix Refreshes two lines at a time Still used on some low-end LCD panels, though not so much with PCs Kiosks Fuel pumps Etc. Largely replaced with TFT Thin film transistor
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 Figure 19: Active-matrix display
Thin Film Transistor (TFT) (continued) The most common TFT displays use a technology called twisted nematic (TN). Most TN displays use only 6 bits for each color red, green, and blue and the 18- bit display will not reproduce the full 24- bit true color that video cards can use. Better TFT displays use a technology called In-Plane Switching (IPS) to create a wider viewing angle and far better color re-creation than TN panels can provide.
LCD Components Backlights (CCFLs) illuminate the image Inverters power the backlights (with AC) LCD logic board uses DC Figure 20: LCD internals
LCD Components (continued) Cold cathode fluorescent lamp (CCFL) used in backlights Inverters convert DC to AC Figure 21: CCFL backlight Figure 22: Inverter
LED Monitors Manufacturers also use several types of light-emitting diode (LED) light for backlighting, either directly illuminating pixels from behind or flooding the panel from the edges of the bezel. Directly illuminating pixels from behind produces outstanding contrast and color but costs a lot more than the edge types. The edge types function similarly to a CCFL-style display, so they produce similar contrast and colors to the older technology.
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 Note: Can change the DPI of entire screen in the Display or Personalization applet. Try Settings Advanced button in XP; left Tasks option in Vista
LCD Components (continued) Brightness Determined by backlight Measured in nits (100 to 1000 with the average at 300) Response rate Similar concept as refresh rate Lower rate (6 8 ms) better Low-end LCDs (20 25 ms) have ghosting problems Refresh rate is locked at 60 Hz or 120 Hz Contrast ratio Difference between lightest and darkest Low end (250:1) to high end (1000:1)
Projectors Rear-view and front-view CRT projectors used first and are expensive LCD projectors light and comparatively inexpensive Today, almost all portable projectors are LCDs
Projectors (continued) Figure 23: Rearview projector (photo courtesy of Samsung) Figure 24: Front-view projector (photo courtesy of Dell Inc.)
Projectors (continued) Figure 25: CRT projector
Projectors (continued) Figure 26: LCD projector (photo courtesy of ViewSonic)
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
Plasma Displays Plasma display panels (PDP) Popular technology for displaying movies, competing directly with LCD screens Offer a wider viewing angle and higherquality image than the typical LCD and cost less, but they weigh a lot more and consume much more electricity than LCDs
Plasma Displays (continued) Two reasons why they are a bad choice for PCs: Burn-in is the tendency for a screen to leave a ghost 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 as PC displays. Overscan is when the TV blows up the image, cropping off the edges of the picture (it can also affect LCD-based TVs).
Common Features Overview Size Connections Adjustments Power conservation
Common Features Size CRT monitors are measured in inches Monitor size (not viewable area) Viewable image size (VIS) screen size from diagonal corners LCD monitors use only the VIS value Figure 27: Viewable image size of a CRT
Common Features Connections Traditional CRT monitors use a 15-pin, 3-row, DB, or D-shell connector and a power plug. LCDs can use DB-15 or Digital Visual Interface (DVI): DVI-D (digital) DVI-A (analog) DVI A/D or DVI-I (interchangeable) Figure 28: A traditional CRT connector
Common Features Connections The Random Access Memory Digital-to- Analog 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 the DVI connection is used, the signal is not translated to analog (RAMDAC not used) Digital signal from video card is sent and used as digital on LCD monitor
Common Features Connections (continued) Figure 29: An analog signal sent to a CRT monitor
Common Features Connections (continued) Figure 30: Converting analog back to digital on the LCD
DVI Details Single-link DVI 1920 1080 @ 60 Hz 1280 1024 @ 85 Hz Figure 31: Dual-link DVI-I connector Dual-link DVI Extra pins to support greater resolution 2048 1536 @ 60 Hz Applies to DVI-D and DVI-I Figure 32: DVI-to-VGA adapter
Common Features Adjustments Controls On/off button Brightness/contrast button Onboard menu system Two main functions of menu Physical screen adjustments Color adjustments Figure 33: Typical menu controls
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 to 30 seconds to restore display
Power Conservation LCD monitor uses less than half the electricity of 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
Display Adapters Two major components Video RAM Stores the video image Video processor circuitry Takes information from video RAM and sends it to the monitor Called the graphics processor unit (GPU) or, less commonly, the video processor unit (VPU) Figure 34: Typical video card
Video RAM Text video cards display only the 256 ASCII characters Older systems displayed 80 chars/row and only 24 rows only 1920 bytes of RAM needed Graphics video cards can turn any pixel on or off Resolution of 320 200 pixels requires 8 KB To add color, add multiple bits 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
Color Depth Color depth is represented as bits Color depth of 24 bits 24 bits commonly referred to as true color Set in Display or Personalization applet Number of Colors Number of Bits 2 colors 1 bit (mono) 4 colors 2 bits 256 colors 8 bits 65,536 colors 16 bits 16.7 million colors 24 bits 16.7 million colors 8-bit opacity 32 bits Figure 35: Adjusting color settings in Windows XP
Transparency in Vista Takes advantage of the 8 bits assigned to opacity Figure 36: Semi-transparency in Windows Vista
Video Modes VGA (640 480 @ 16 colors) Table 1: Typical Display Modes Video Mode Resolution Aspect Typical Device Ratio SVGA 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 WXGA 1366 768 16:9 Widescreen laptops 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 QWXGA 2048 1152 16:9 For smaller, fine monitors WQXGA 2560 1600 16:10 For 27"+ widescreen monitors WQUXGA 3840 2400 16:10 For smaller, fine monitors
Video Memory Minimums Resolution color depth = memory needed Common modes and the minimum video memory needed: 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 2: Common Modes and the Minimum Video Memory Required
Motherboard Connection PCI slots 800 600 with a 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 Figure 37: AGP
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
AGP Benefits (continued) Figure 38: An AGP bus
AGP Benefits (continued) Figure 39: AGP 8 slot
PCIe (PCI Express) Developed to replace PCI Designed to replace AGP also Incredibly fast serial communications Supports many of the AGP benefits Sidebanding System memory access Figure 40: PCIe video card connected in PCIe slot
Graphics Processor Unit The most important decision in buying a video card is the graphics processor unit (GPU). Good GPUs are made by NVIDIA AMD Intel NVIDIA GeForce GTX 260 1 GB Nvidia Manufacturer GeForce Branding GTX 260 Processor and model 1 GB Amount of RAM
Graphics Processor Unit (continued) Figure 41: NVIDIA GeForce GTX 570
GPU (continued) Manufacturers release multiple models of GPUs each year. Most features seen only in 3-D games: Textures Transparency Shadows Reflection Bump mapping GPUs are very powerful parallel processors.
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
Video Memory (continued) 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 Figure 42: Wide path between video processor and video RAM
Video RAM Technologies Table 3: Video RAM Technologies 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
Video RAM Capacity The amount of dedicated video RAM on cards increases with almost every new video card. What s common today? Check newegg.com or directron.com to find common video RAM sizes. What s the sweet spot in price/performance? 128 MB of RAM? 256 MB of RAM? More? Less?
Integrated GPUs Most current motherboards have or can support integrated GPUs. Motherboard GPU can be a separate chip attached to the motherboard, or it can be built into the Northbridge chip. Three main manufactures all provide chips that vary in performance and combination. With an integrated GPU, the CPU circuitry can get crowded, but the chip requires far less electricity than comparable discrete components.
Integrated GPUs (continued) Many techs and companies call current integrated GPUs accelerated processing units (APUs).
Connector Types and Associated Cables Video cards offer a variety of connections. Standard connections include One or more DB-15 (VGA) ports One or more DVI ports DisplayPort (Mac) Video card makers offer all sorts of other connections to integrate video cards with other multimedia.
Connector Types and Associated Cables (continued) Figure 43: Video card connectors, VGA, S-video, and DVI-I
Connector Types and Associated Cables (continued) Mini-DIN connectors S-video Proprietary These offer connectivity to televisions for output and to video cameras for input. DisplayPort Popular on Macs DVD, Blu-ray Disc player, or video camera may use S-video, Mini DIN, or proprietary.
Connector Types and Associated Cables (continued) Figure 44: DisplayPort jack
Connector Types and Associated Cables (continued) Figure 45: S-video and proprietary round connectors
Video Card Connections TV Out connects computer to TV Tuner card Enables PC to mimic some features of TiVo High Definition Multimedia Interface (HDMI) Designed to replace DVI connections Supports High-Bandwidth Digital Content Protection (HDCP)
Video Card Connections (continued) Figure 46: Composite and component connection options
Video Card Connections (continued) Figure 47: HDMI port on Lenovo laptop Figure 48: DVI-to-HDMI cable Figure 49: Mini HDMI port
Lab What s in the Box? The student PC has built-in video: Who is the manufacturer? How much memory does it have? What connectors does it offer? Can you upgrade the video? How? What resource(s) can help you get answers to all these questions?
Installing and Configuring Video Once you ve decided on the features and price for a new video card, you need to follow common procedures for installing and configuring. These include: Physical installation Install drivers Display applet or Personalization applet configuration Update drivers if you didn t do that initially
Physical Installation Issues Two primary issues 1. Long cards Some video cards are long and may not fit in all cases Get a new case or new video card Figure 50: Installing a 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
Software Install drivers for the video card and/or monitor. Windows has some built-in drivers, but these may be out of date. Alternatively, you can use the installation CD that came with your video card. Use the Display applet in the Control Panel to make adjustments to display settings. As with all other devices, you want to ensure your drivers are up to date.
Display Applet The Display applet in the Control Panel provides a central location for all display settings, including resolution, refresh rate, driver information, and color depth. With Windows XP, the Display applet has five tabs by default: Themes Desktop Screen Saver Appearance Settings Figure 51: Display Properties dialog box in Windows XP
Display Applet (continued) Settings tab: Allows you to adjust the resolution, color depth, or to add monitors. To use additional monitors, either add a video card or use a video card that supports multiple monitors. Once connected, select Extend my Windows desktop onto this monitor on the Settings tab. Microsoft calls this feature DualView.
Display Applet (continued) Settings tab (continued): Clicking the Advanced button opens up additional menu choices, General, Monitor, and Adaptor: Refresh rate is under the General tab. If there is no setting for the refresh rate, you do not have the proper monitor driver loaded or you have an LCD (they have a fixed refresh rate). Should try at least 72 Hz or higher, if your monitor supports it. Setting the refresh rate too high may limit the color depth or resolution. Setting the refresh rate higher than your monitor can handle may cause physical damage.
Display Applet (continued) Settings tab Advanced button (continued): You can update the drivers for the monitor from the Monitor tab. On the Adapter tab, you can choose to List All Modes. This may give you additional choices.
Display Applet (continued) The Personalization applet in Windows Vista offers functions similar to the Display applet, but as clickable links rather than tabs. Themes, Desktop, and Appearance tabs are focused on making the screen pretty. The Screen Saver tab has access to power management features.
Display Applet (continued) Figure 52: Personalization applet in Windows Vista
Display Applet (continued) Figure 53: Personalization applet in Windows 7
Display Applet (continued) Figure 54: Theme option in the Windows Vista Personalization applet
Display Applet (continued) Figure 55: Desktop tab on Display Properties dialog box
Display Applet (continued) Figure 56: Desktop Background options in Windows 7
Display Applet (continued) Figure 57: Advanced Appearance dialog box in Windows XP
Display Applet (continued) Figure 58: Window Color and Appearance options in Windows 7
Screen Saver Screen Saver option goes beyond just displaying a nice image on the screen. Can also configure display power management. Figure 59: Screen Saver Settings in Windows 7
Screen Saver (continued) Figure 60: Power Options applet in Windows 7
Advanced Settings You ve already learned about the Settings tab (XP) and the Display Settings applet (Vista) Enables altering refresh rate Enables altering screen resolution Offers other options too DualView Vendor-specific tabs very common, enabling you to tweak 3-D settings
Settings/Display Settings Allows you to configure multiple monitors in DualView mode (desktops and laptops) Figure 61: Display Settings applet and Settings tab
Settings/Display Settings (continued) Figure 62: Display applet in Windows 7
Settings/Display Settings (continued) Figure 63: My editor hard at work with dual monitors
Settings/Display Settings (continued) Figure 64: Enabling multiple monitors
Settings/Display Settings (continued) Figure 65: Advanced video settings, Adapter tab
Settings/Display Settings (continued) Figure 66: Advanced video settings, Monitor tab
Settings/Display Settings (continued) Many video cards have card-specific tab Figure 67: Third-party video tab
Settings/Display Settings (continued) Card-specific tab offers options Color Correction Can adjust screen colors Rotation Portrait or Landscape Modes Very advanced settings Usually not needed Figure 68: Portrait mode
Working with Drivers Video drivers work the 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 cards Figure 69: Adapter Properties dialog box
3-D Graphics Improvements driven by games Also used in other applications such as computeraided design (CAD) First-person shooters (FPSs) such as Wolfenstein 3D and Doom started move to 3-D Figure 70: Wolfenstein 3D
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 Figure 71: Each figure had a limited number of sprites.
3-D Objects The second generation produced 3-D objects through a process called rendering. Objects are composed of a group of points or vertices. Vertices were connected with lines (called edges). Edges form triangles that create polygons. The last step is adding a texture (or skin).
3-D Objects (continued) Figure 72: Vertices for a video game warrior
3-D Objects (continued) Figure 73: Connected vertices forming polygons on a 3-D character
3-D Objects (continued) Figure 74: Video game warrior with textures added
3-D Video Cards Graphics processing units needed: Realistic movement required screens to be 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) were created to talk to hardware directly, enabling standardized instruction sets: OpenGL ported from UNIX DirectX (Microsoft only)
DirectX and Video Cards DirectX provides direct access to hardware and is used for more than just video: 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
DirectX Diagnostic Tool Accessories System Tools System Information Tools DirectX Diagnostic Tool Or... Start Run or Start Search DXDiag Figure 75: The DirectX Diagnostic Tool
Freeform Lab Run DXDiag Chose either way to get to the tool System Information Run/Start Search dialog Run DXDiag What does it reveal about the video capabilities of your laptop or student PC? What version of DirectX is installed? Did the video card pass all the tests?
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
Video Card Problems Vast majority of problems are Improper or corrupt drivers Incorrect settings Incompatible or corrupt driver symptoms 640 480 mode 16-color VGA Windows Stop Error (BSoD) Your response Boot to Last Known Good Configuration Boot into Safe mode and remove driver Use Add/Remove Programs if available Use Device Manager
Video Card Problems (continued) 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 Figure 76: Serious video problem
Video Card Problems (continued) 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
Troubleshooting Monitors Opening 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!
Troubleshooting Monitors (continued) 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
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
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
Troubleshooting Monitors (continued) 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 push the button! Disregard the loud thunk sound it s normal.
Common Problems LCDs Symptoms Cracked LCD monitors are not repairable. Flickering image: too much light bleed from the backlight or a dying CCFL backlight Dim image: a dead or dying backlight LCD goes dark: lost either lamp or inverter Hissing noise: inverter is about to fail 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
Common Problems LCDs (continued) Figure 77: LCD components labeled
Cleaning Monitors Antistatic monitor wipes or antistatic cloths should be used for cleaning the monitor Do not use window cleaners Avoid commercial cleaning solutions on LCD screens Never spray onto the monitor, spray the cloth Can use mild soap and water
Safety Concerns Safety Concerns Avoid the inside of a CRT. Always practice good cable management to prevent cables from getting snagged, pulling monitors to the floor. Use proper lifting techniques (use your legs, not your back) and pay attention to monitor-stand weight limits. Always take a monitor CRT or LED to a proper recycling center.
Troubleshooting Playback Troubleshooting Playback Errors with HD playback include Blu-ray Discs or downloaded HD movies. Usually involves an HDCP issue all equipment, including video card, monitor, and cable, must support HDCP. Only HDMI, DVI, and DisplayPort cables support HDCP VGA doesn t.
Troubleshooting Playback (continued) Figure 78: HDCP error
Beyond A+ Digital Light Processing (DLP) displays use a chip covered in microscopically small mirrors. The 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. A 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.
Beyond A+ (continued) DLP was very popular for a time in home theater systems and projectors, as it produces a high-quality image, but it has had very little impact on PC monitors because of its high cost. Figure 79: DLP chip (photo courtesy of Texas Instruments) Figure 80: Microscopic close-up of DLP showing tiny mirrors note that some are tilted.