I have a Dell monitor I bought about 3 years ago and it suddenly started flickering constantly. I've already tried it with another HDMI cable and on a different computer and it's still doing it. Is it a problem with the monitor itself or is there something I can do before throwing it out?
If you've already ruled out cables and tested it on another computer, it's most likely an internal monitor failure, but before you write it off try this: unplug the monitor from the outlet, wait a couple of minutes full stop (not just 30 seconds like some people suggest), and then plug it back in. It sounds silly but sometimes the power circuit gets stuck in a weird state and this resets it. While it's unplugged, also check if there's dust inside the monitor's ventilation grilles, sometimes buildup causes thermal issues that create these flickering problems.
If that doesn't work, the next step would be to check if your monitor has an OSD menu button on the front and access the brightness and contrast settings, because sometimes something gets configured weirdly in the internal electronics. I had a friend years ago with a Dell that did exactly what you're describing, flickering every two seconds like it had a nervous tic, and it turned out there was a capacitor about to blow on the monitor's circuit board. He ended up taking it in for repair and it was pretty cheap, I think it was around 40 euros for labor.
What I will say is that at three years old it's not unreasonable to get it checked out before you toss it. Dells aren't the most reliable over time, but they don't wear out that fast either. If you find a decent technician, they'll give you a diagnosis for free or next to nothing.
Try restarting the monitor by turning it completely off for 30 seconds and then turning it back on, because a lot of times it gets stuck in an error loop; if that doesn't work and you've already ruled out cables and different computers, it's most likely an internal problem with the panel or the monitor's electronics and at that point it would need to go in for repair or straight to the trash, but before that try that restart since it doesn't cost you anything!
When my computer starts with those weird flickering things, it's almost always something loose in the connection 😅 but you already tried it with another cable and another PC, so yours looks like a backlight failure or an internal driver issue in the monitor. If you don't want to toss it yet, try getting into the monitor's menu (the side buttons) and reset it to factory settings, sometimes these things get stuck in a weird state. If it keeps flickering the same way after that, unfortunately it's probably the monitor itself, and at this point in its lifespan it's time to call it 🤷♀️
I've seen monitors with that problem and it's almost always - once you've ruled out cables and another computer - the backlight failing or a burned capacitor on the board. What nobody mentions is that some Dells have a reset button on the back (or via USB) - check your manual if yours has one, because actually resetting the monitor's electronics sometimes saves the day.
If that doesn't work, it's a motherboard issue on the monitor itself and there's not much more you can do without getting into soldering.
Have you checked if the flickering also happens in the monitor's settings menu (without video signal)? Because if the problem goes away when you enter the settings but comes back as soon as you connect a device, it could be a synchronization or signal processing issue in the monitor's motherboard, not necessarily the backlight. In that case, sometimes updating the firmware (if your Dell has that option) or completely resetting the monitor to factory settings from the menu can help, even if you've already restarted it. If the flickering is constant even without a signal, then yeah, it looks like an internal failure, but you can check that in a minute first.
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