Question Display flashing on and off - even if hdmi is not plugged in

Mar 18, 2025
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Hi everyone,

Today, for the first time ever, my secondary display has started flashing on and off. I updated the Nvidia drivers to be sure, but it kept doing so. When I disconnected the hdmi cable from the screen (not from the GPU), the screen turned blue (normal when there is no signal), but the weird thing is that it kept flashing on and off.

At this point, I guess there is no problem in my GPU (which is the best news), but is it something common? Is there no way to fix it?
After I reconnected the cable, the screen kept flashing for a couple of seconds, now it has stopped, but I don't know if and when it will resume.

Screen is a (roughly) 10 year old BenQ GL240H
 
Unfortunately it doesn't seem to be the power cable. It happened again after a long stand-by during which the screen had gone into energy save. I don't know if it might be related... At the moment, after a couple of minutes of powering up again, it has not stopped.
 
Update: after around 10 minutes it stopped flashing on its own. It looks like it needs to get warm. The room is quite cold compared to the rest of the house, around 16-17°C (~60-62F). Could it be anything related to temperature? And is it fixable?