CompTIA A+ Core Certification: The Basics of Hardware and Network Troubleshooting - Troubleshooting Video, Projector, and Display Issues

220-1101: Objective 5.4: Given a scenario, troubleshoot video, projector, and display issues.
Desktop, laptop, and mobile devices each have screens that can vary significantly, and projectors can add another layer of complexity. Setting up a meeting, training, or conference space is a common assignment for a technician. It is important for the technician to arrive early and test all the equipment before the start of the event. If possible, have the presenter come even before the attendees arrive; every technician wants to avoid the pressure of an audience while trying to troubleshoot a projection issue. This section lists some common issues that arise when setting up a projector, as well as how to diagnose and fix them.

Incorrect Data Source
Projectors come in a variety of sizes, and each has its own way of accessing data to project on a screen. They can project from laptops, gaming consoles, phones, tablets, and almost any device that can be shared. If the screen is lit up but the device is not being replicated on the projection screen, the likely problem is that the projector is looking elsewhere for input. From the menu options, look for the source submenu. The inputs are likely looking for a cable interface for incoming data, but if the cable from the device is plugged into HDMI port 1 and the projector is set to look at HDMI port2, nothing will happen. This sounds easy to fix, but it is a common problem because many projectors are wall mounted and the HDMI and other inputs can be hard to access, let alone read their labels. If everything else looks like it should be working, try scrolling through the source menu to see if the projection shows up on an interface other than the one expected.

Physical Cabling Issues
Physical cabling issues are the first problems to troubleshoot. Any networking professional can tell a story about troubleshooting for a complex problem, only to find that the physical cable was the problem.
Always start the troubleshooting at the physical cables before you troubleshoot more complex configurations and software. When machines are moved during setup, cables come loose in their sockets or become disconnected altogether. If a projector will not light up, check the indicator lights or listen for a fan; if you cannot find a problem there, physically check the power connectors—sometimes, they appear to be connected but have come loose and are not conducting power. This is also true for HDMI, coax, Ethernet, or any cable the projector can use.
If the physical cable is plugged in, make sure it is in the right interface, as stated previously with data source selection. These fixes sound easy because they are—however, it is very common to encounter problems that have simple solutions. Think basic first.
Tip: HDMI cables are preferable to other types because they carry high-definition video and also audio. HDMI cables are also compatible with most devices. The fewer cables are needed, the less likely physical cable issues will occur.

Burned-Out Bulb
Light bulbs in projectors can burn out for several reasons. Eventually, they will all burn out. Always have the right replacement bulb on hand. If more than one model of projector is in inventory, be sure to have bulbs that match and make them easy to access.
It is always best to replace a bulb before it burns out, but bulbs can be expensive and it is hard to know how much longer they will last. Some projectors have LED indicator lights that warn of a potential bulb failure from excessive hours in use. The following are other possible indications:
- A bulb might dim, noticeably affecting the image being projected.
- If images are not crisp and bright or colors are faded, the bulb might no longer be at full strength.
- The image might flicker, indicating that the bulb is about to fail.
- The bulb might simply go dark, but the fan keeps running. Sometimes a loud pop is heard as the internal workings of the bulb fail.

Intermittent Projector Shutdown
Projectors shut down when they overheat. To avoid overheat shutdown, check the following:
- Clean or replace filters when recommended. Projectors with filters usually display a message onscreen when it is time to clean or replace the filter.
- Make sure the projector has adequate ventilation.
- Check air intakes and exhaust ports for dust and dirt, and clean as necessary.
- Use a lower brightness setting on projectors, to reduce heat.
- Be sure to allow the projector to cool down completely before removing it from power.
A video card (GPU) that overheats usually displays screen artifacts before shutting down.

Dead Pixels
Dead pixels (black pixels) typically result from manufacturing defects in an LCD screen. Check with the manufacturer of the display panel or laptop to determine the number of dead pixels that are needed to qualify for screen replacement.
Some “dead” pixels are actually stuck on (bright) or off (dark). This problem can be solved in a variety of ways, including the following:
- Navigate to the JScreenFix website (www.jscreenfix.com) and start the pixel fixer app. Drag the app window to the area of your screen with the pixel problem and leave it over the area for up to 10 minutes. JScreenFix uses HTML5 and JavaScript controls in the web browser. It works with any LCD or OLED device, including mobile devices.
- Gently massage the stuck pixel with a stylus or another object with a blunt, narrow end. See www.wikihow.com/Fix-a-Stuck-Pixel-on-an-LCD-Monitor for illustrations.
- For Windows systems, download and run the UDPixel utility (https://softradar.com/udpixel/). It requires .NET Framework 2.0, which can be added to Windows 7/8/8.1/10 through Add/Remove Windows Features (in the Control Panel).

Incorrect Color Display
Incorrect color display on a projector can have several causes, so try the following:
- Check the signal type in the projector menu, and change it if it is incorrect.
- If one LCD panel (red, green, or blue) is failing in an LCD projector, replace the panel. Panels often fail because of the impact of ultraviolet light causing excessive heat and breaking down organic compounds used in the process.
- On a DLP projector, check the LED light sources (red, green, or blue) or dichroic mirrors.
- Clean the projector LCD panels if odd-colored specks are visible.
- If a laptop has been serviced or upgraded, the LCD ribbon connector to the motherboard might have been damaged. If an external display works correctly, check the LCD ribbon cable inside the laptop.
- Check a VGA cable for bent or broken pins. (However, some pins are not present, by default.) Check all video cables for cracked outer casings and loose or damaged connectors.

Dim Image
A dim image can be caused by settings issues or by equipment failure. Check the following:
- Check the screen brightness control on a display or projector. As mentioned earlier, it could mean a bulb is close to failure.
- If a display management program is being run (which is common on Intel, NVIDIA, and AMD 3D GPU drivers), check its settings.
- On a laptop, tablet, or mobile device, check the built-in screen brightness setting.
- On a projector, check the projector bulb. A bulb can become milky, which reduces light output, near the end of its service life.
- On a device that uses a CCFL backlight, check the inverter. A failing inverter can cause a dim display before the inverter fails. The inverter can be replaced separately from the LCD panel or backlight.

Flashing Screen
A flashing screen can have many causes:
- Before you look at hardware replacements, try updating the GPU (video card) or chipset drivers.
- On displays that use an LCD-CCFL backlight, flickering can be caused by a failing inverter or a failing backlight. Inverters are relatively inexpensive and can sometimes be replaced without a complete teardown. Backlights cost more, and it could make more sense to buy a replacement LCD screen or retire a computer or display.
- On any type of LCD display (CCFL or LED backlight), loose internal cables can cause flickering. A two-in-one convertible device (tablet/laptop) could have a hinge problem that can lead to flicker.
- On desktop computers, check the power connector to the PCIe card (if it uses a separate power cable) and the power supply itself. If the problem happens after the computer has been running for a while, it could indicate a heat-related problem.

Fuzzy or Distorted Image
A fuzzy or distorted image can have several causes and solutions, including the following:
- If image tearing or distortion occurs in 3D games only, change video drivers. In most cases, the newest video driver is recommended; in a few cases with certain games, the best short-term fix might be to install an older driver. Check driver versions with Device Manager’s properties sheet or the proprietary app installed by your GPU or video card maker.
- Distortion with DisplayPort connections can be caused by problems with the way some DisplayPort cables and connectors are manufactured. If you can use a different connection (DVI or HDMI) between a system and a display, and the problem is no longer present, replace the DisplayPort cable.

Display Burn-in
Burn-in, the persistent display of a “ghost” image onscreen that was displayed previously, even after the current screen contents have changed, can affect both LCD and plasma displays.

LCD Displays
With LCD displays, stuck pixels are the usual cause of burn-in. Programs that run constantly changing patterns across the area, such as the previously mentioned JScreenFix or UDPixel, can be used to fix this problem.
Another solution is to create an all-white image using a graphics program, set it as the screen saver, and turn down the display brightness. Leave the screen saver running about as long as the original image was onscreen.
To avoid image persistence with IPS displays (the most common type of LCD display in use, offering wide viewing angles), Apple recommends using display sleep to turn off the display when idle. To eliminate a persistent image, enable the screen saver to come on before display sleep, and run it as long as the persistent image was originally onscreen. For more information, see https://support.apple.com/en-us/HT202580.

Plasma Displays
Plasma displays use phosphors, which can wear unevenly over time. This is also the cause of burn-in on CRT displays. To avoid either temporary or permanent image persistence, try the following:
- For customers who watch mainly 4:3 ratio TV or movie content, advise periodically switching to full-screen (zoomed) mode, to avoid black bar persistence on the sides of the image.
- Use the screen clean (screen washing) option available on some plasma HDTVs. This puts a constantly changing display across the entire screen.
Tip: For plasma and LCD display/HDTV users, many YouTube videos can be played to help fix image retention. To play these on an HDTV, go to the YouTube app and search for “image retention fix.”

Audio Issues
If audio issues arise with a device that is plugged into a projector, first make sure that the audio is working on the computer. Sound cards in mobile devices are usually mounted on motherboards in smaller devices and rarely fail. However, simply unplugging the device from the projector and trying the sound ensures that the computer’s audio is not the issue. If you do find a problem, removing and replacing sound drivers is a good place to start.
Audio issues on projectors are similar for any audio output device. The first area to check is cable connections. If the connections are fine, look to the source’s output settings to see if the output is set to HDMI/USB (if that is being used). If it still fails, try swapping the cable for a known-good cable to make sure it is not a physical issue.
If the audio is buzzing, it could be caused by electrical interference in the room. Make sure the projector and the source device are plugged into the same outlet bar, to eliminate this issue.
If the volume is too low or too high, remember that there might be multiple volume controls—one on the source device, one on the projector, and maybe even one on the software being presented.
No sound from speakers can result from several causes:
- With wired speakers, keep in mind that the case might prevent a 3.5mm mini-jack connector from making a good connection. You might need to remove the case to make a good connection.
- With Bluetooth speakers, make sure Bluetooth is turned on. Check device pairing.
- Check the volume or mute controls on the mobile device. Apple iPhones have a sliding switch to mute them, as well as software controls. The side button on an iPad can be configured to lock the screen or mute speaker output. Check the volume control on the keyboard or OS on macOS and Windows devices.