Argthtjtr

I have installed an external monitor (Dell ST2220L, 21.5 inch) on my laptop (Sony Vaio). I am using a DVI-D cable for connection. Since the laptop does not have a DVI-D port, I have connected a DVI-D to HDMI connector on the laptop end and inserted the cable in HDMI port of the laptop..

I have switched off the laptop display and adjusted the screen resolution on the Dell external monitor to 1920 x 1080 and adjusted colors for the Windows 7 and brightness and contrast from the monitor.

The problem is the monitor turns of blank intermittently for 1-2 seconds and turns on again at random interval. What could be the reason for this and how to get rid of this problem?

This seems to be a connectivity issue. Try and wiggle the adapter, and all the connections while powered, and see if you can make the problem appear. Don't forget to test the connection at the display too.

I believe it's most likely a bug in the generic Windows display driver. It's possible you can solve this with a driver from Dell for your display.

I've struggled with exactly that same behavior in one of my monitors, where it randomly goes dark for a couple seconds, then comes back on. The interval between could hours or it could seconds (almost constant flickering.)

In my case, it's two Dell 2405FPW panels side-by-side on my desktop and the problem only presented on my left monitor. Web searches at the time confirmed this a common problem, but seen only on the then-new Windows release I was running and could be traced to Dell having dropped support and not releasing a driver. The random behavior was because I was using the default driver. It drove me nuts for years (but I was too cheap to buy new panels that were supported.) The problem finally (fingers crossed) appears to have gone away a couple months ago with an Nvidia update for my graphics card.

In your case, I don't see others reporting the same behavior with your model and it looks like Dell still supports your monitor. But the behavior you're seeing is exactly what I saw from the default driver. This is why I suspect it may be as simple as downloading the proper driver from Dell.

Good luck. I hope this helps.

I believe it is an HDMI issue as I am having the same problem with a new Vizio 50-inch LED TV. When using HDMI to watch cable tv or Blu-ray discs I get intermittent "no signal" displays where both video and audio disappear for a couple of seconds and then come back. Using component connections I don't have that problem. I don't like using component since the picture quality is not as good, but I can't find a better solution for the time being.

I had the same problem with a Dell U2515H screen that turned blank for a second or two now and then. Had the newest drivers installed for both the graphics card and the monitor.

Was able to solve it by disable "DP 1.2" (had enable it previously to allow daisy chain of two monitors).

There are many reasons why a monitor keeps turning off, resulting in
a blank display. The best way to resolve this problem is through
process of elimination; as such, I will go through the list of things
you can do to help determine why the monitor keeps going black or
turning off sporadically.

Simply put: both DVI and HDMI are digital signals; if the signal is
too weak, the monitor won't sync to the computer, resulting in a blank
screen. If the cable run is too long, or of the signal has been split
(using a non-powered DVI or HDMI splitter), this can cause the monitor
to go black because the signal isn't strong enough.

Based on my experience, some HDMI cables will simply stop syncing
properly after a while, even though they worked fine previously, and
even though the same cable works fine on another device. Sometimes,
HDMI cables won't work properly if there has been a recent hardware
configuration change. For example, you may have purchased a stereo
receiver and ran the cable through the receiver instead of directly
through the monitor. In this case, you can bypass the splitter or
receiver and see if that makes any difference.

https://www.infopackets.com/news/9589/how-fix-monitor-keeps-going-black-turning

I had this exact same problem with a Surface Pro 4, Monoprice monitor MP-28UHDSS. Seemed to start happening after the Windows 2018 May Update. I tried various suggestions, none worked for me until I went to Advanced Display Settings, Display Adapter Properties, and found that the screen refresh rate was set at 59Hz. No idea where that came from. I changed to 30Hz, and problem is definitely gone.

This is going to sound crazy, but I have solved this and other external display issues in Windows 10 by simply logging in as an administrator on the computer. Then I can log out and back in as my regular user, and the issue is gone!

I usually run Windows as non-admin, and it seems Windows wants to "do things" with regards to the monitor that it needs administrator rights to do. Weird that I get no notification whatsoever about this.

(Edit 1: It seems like I have to always remain logged in as an administrator in the background, and switch to my regular user, for the issue not to appear again.)

(Edit 2: Like I have read on other places, these kinds of fixes usually only work for a short while, so the problem was NOT solved.)