Given a scenario, troubleshoot common video, projector and display issues: CompTIA A+ Exam 220-901 sub-objective 4.3

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Detailed (and official) description of CompTIA A+ sub-objective 4.3:

4.3 Given a scenario, troubleshoot common video, projector and display issues.

Common symptoms
– VGA mode
– No image on screen
– Overheat shutdown
– Dead pixels
– Artifacts
– Color patterns incorrect
– Dim image
– Flickering image
– Distorted image
– Distorted geometry
– Burn-in
– Oversized images and icons
Welcome to ExamNotes by CertBlaster! In this installment we will troubleshoot some of the more common video problems you’ll need to know about.

Common Symptoms

VGA mode

Accessed in the Advanced Boot Options by pressing the F8 key at startup Windows will offer VGA mode as a boot option. Newer versions (8.1-10) refer to it as low resolution video. In either case we are referring to is the most basic video resolution and color setting available. The purpose is to successfully access the system using the standard VGA driver as opposed to the manufacturer’s driver. Using the standard driver enables you to see your system while reducing the video systems impact on system operation. In this mode your on-screen objects may appear larger or geometrically distorted. You will have the ability to troubleshoot the system. Shown here is the Windows 8.1 access method. Here you would press F3 to access low resolution video

Screenshot of the blue startup settings screen
Startup settings in Windows 8.1

No image on screen

There are a variety of possible causes for this condition. Troubleshoot this condition as you normally would any hardware issue. Start with the obvious, is the computer operational? That would entail power fans lights all running. Obviously there will be no image on the screen. Do check the monitor (if it applies) for Power indicator lights and check the cable connections carefully. If everything is in order you would next try a different monitor on the system. If these steps fail grab your user manual there may be a reset sequence.

Overheat shutdown

In the video system any heat related issues are most likely to be associated with the graphics subsystem. Often the demands of high quality video, rapid frame rates and millions of colors combine on the video chipset, which may even be part of the processor. The byproduct of this is heat and although Heat exchangers, pipes fins and fans are capable of dissipating the heat, they can have their effectiveness reduced by its only natural enemy, dust. If you find a slight layer of dust in the fin housing under the fan blades blocking airflow that could be sufficient to impede the cooling capacity of the cooling unit. Variations in temperature especially hot may cause the system to shut down protectively. Easy enough to clean and important enough to check regularly.

Here are some of the terminology you are going to need to be familiar with:

Dead pixels

A dead pixel is a picture element on an LCD panel that remains unlit despite the fact it should be displaying a color or light of some type. It will probably remain black.


Although they usually appear as a small segment of corrupted screen output, we’ll show the most extreme illustration of it we could find. Here is a screen full of artifacts.

Screenshot of pixelised artifacts i.e. corrupted screen output
“Artifacts” – Corrupted screen output

In the 1970’s this condition would be remedied by striking the display which, as strange as it sounds, would work for short periods by reconnecting broken tube filaments. This archaic technique will not work with solid state components. Repairs can be attempted using manufacturer designed software as sometimes a driver patch saves everyone money and man hours.

Color patterns incorrect

This condition will be present in a new “out-of-the-box-monitors”. If the Colors are distorted or obviously wrong you can start by power cycling the monitor. If that fails consult documentation for the Calibration routine or use Windows built-in Calibration wizard.

Dim image

More often than not a dim laptop image will be the result of power saving settings on a laptop, Or ambient light setting on a flat panel TV. The condition is remedied using the monitor’s controls

Flickering image

A flickering image is the result of the monitor running below 60Hz. At or above 60Hz the human eye cannot detect changes in an image. That is to say that if you display progressive groups of images at 60 frames per second those images would appear to simply flow along. If you take those same images and display them at 50 images per second they will appear to stutter as each new image is recognized.

Distorted image and geometry

Images on your monitor are displayed using a strict X-Y axis. X pixels high by Y pixels wide. 1024 by 768 is reproducible by most monitors. In the clearest case a perfect circle is input, variations to either of the x-y values will result in an imperfect circle, possibly an egg shape. Here we will show the   result of a perfect grid of squares displayed at the wrong geometry.

Graphic showing distorted-geometry
Distorted geometry

This is resolves by setting your monitor to a standard resolution. A very commonly observable example of this condition is with today’s flat panel wide screen monitors displaying old television shows. The old content appears stretched, short and fat.


Finally just about the worst thing that can happen to a monitor with years of useful life remaining is a condition called burn-in. This happens when a single motionless high contrast image is displayed for a long period of time, like a day. The result is the image is “burned-in” or ever-present on the display, showing constantly, faintly but constantly.

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Ok folks that’s it for 4.3. Good luck on the test!

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