The video cards installed in computers continue to improve and provide newer features such as higher resolutions and refresh rates.  This sometimes introduces some unexpected results when connected to various external video sources such as no signal and or flickering signals.  When this situation occurs it can be a very distressing situation, that can be remedied  fairly quickly with a settings change.

MacOS Ventura:

  1. Click on the Apple, located on the menu bar in the upper left corner of the screen, and from the drop down menu select the option for System Settings.
  2. In the window that appears, use the column on the left to  find the option for "Displays" and click on it.

    Did you know you can use the search bar at the top of this column to quickly access settings and controls when you are unsure of their location.

    Image of the System Settings Search Bar

  3. The right side of the window will update to show all of the displays connected to the computer in the top portion of this area.  Click on the display you would like to adjust.
  4. The lower portion of the right side window will reload to showcase what features can be adjusted for the selected display.  Find the section for "Refresh rate" and set it to 30 Hertz.  This change is set once selected.

Image of the Display options with the refresh rate set to 30 circled in red

It may take up to 30 seconds for the changes to take place and update to all the devices.  If the change does not result in your image being presented you may need to switch to another input on the teaching station, then back again before the change is detected.