10.3.1 Video Troubleshooting

Learn methods to properly troubleshoot video and display issues on computer systems.

The video system has three components: the adapter, cable, and then the display device (e.g. monitor). Video display issues can arise from problems with any one of these components.

Issue: No Display

Check the simple causes first:

• power on
• monitor is plugged in and powered on
• monitor is properly connected to the video board
• monitor isn't in Power Save mode

Then you can check that it:

• isn't a failed monitor
• a failed video board (GPU)
• a failed power supply or a damaged cable that isn't sending power to the monitor
• video board hasn't been jostled out of it's slot

Issue: VGA Mode Automatically Enabled

VGA mode can be observed by it's signature 640x480 resolution and 16-bit color depth. VGA mode is almost exclusively enabled by a missing, broken, or incompatible video board driver.

VGA mode might also automatically turn on when the user boots into Safe Mode on Windows. This is because Safe Mode ensures maximum hardware compatibility, which the Basic Video Driver provided by Windows has perfected.

Issue: Dim Image on a LCD Monitor

Usually caused by one of two things:

• misconfigured brightness setting
• malfunctioning LCD backlight

Since LCD monitors don't produce a lot of light, it relies on a backlight for images to be visible to the end user. This backlight relies on two components, the backlight itself and the inverter that's powering it. Either the backlight has burnt-out or the inverter is malfunctioning. If you can't repair the monitor, you'll have to replace it in many cases.

Issue: No Video but Audio

This is caused by having the correct audio codec installed. When playing a video file, the system needs to support both the audio codec and video coded used by the file. If the audio plays but the video doesn't, you're missing the correct video codec.

Color Calibration

To calibrate your monitor, you want the PC to reach running temperatures, set the monitor to it's default settings (native resolution, 32-bit color depth) then print out a copy of the screen on high-quality color paper. You then adjust the color settings of the monitor to match what's printed on the paper as much as possible.

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