Ace the CBET Challenge 2026 – Master Biomedical Equipment with Style!

When an LCD video display produces a purple image in RGB mode, this indicates that the red and blue channels are functioning correctly while the green channel is not contributing any output, leading to a blend of red and blue light, which appears purple to the human eye.

In this scenario, the most likely cause would be a problem with the video signal that relates specifically to the green channel. A bad video cable connection in the green channel would prevent the green color signal from reaching the display, resulting in the absence of green illumination alongside the active red and blue signals. As a result, the image will lack the green component, producing a predominantly purple appearance.

Adjustments to controls or saturation levels would not cause the issue seen if the green channel is entirely nonfunctional due to a bad connection. Similarly, while a defective green gun in the video display could cause a similar issue, a cable fault is more likely the immediate factor when determining why the green signal is not being displayed.