Monitor power cable making some sort of buzzing noise

[Bill_Bright]

The slight crackle as you plug in a power cable that’s connected to the mains is normal, yes.

It is common if that sound is coming from the power connector (the plug prongs or inside the wall receptacle) itself as it is plugged into, or pulled from the wall - if truly "slight" and you don't see any sparks. Not sure I would call it "normal" however. I recommend you be more deliberate (and quick) when plugging in and unplugging. Arcs (sparks) occur as the two conductors come near or move away from each other. The faster you are, the less chance of an arc - or at least you hopefully minimize it to one smaller arc.

Arcs are not good because they result in carbon buildup where the arc jumped across the gap and made contact with the other conductor. Carbon is the basic component of resistors. Over time, that carbon buildup can result in failed connections, or even excessive heat. Not good.

If your power cord looks like this where there is some distance between the wall connector and the AC/DC transformer so you can easily tell for certain that the "slight crackle" is coming from the transformer and not the power plug, that is NOT normal at all and the power supply needs to be replaced ASAP.

I would also recommend you check your wall outlets. Every home and every computer user should have access to a AC Outlet Tester to ensure your outlet is properly wired and grounded to Earth ground. I recommend one with a GFCI (ground fault circuit interrupt) indicator as it can be used to test bathroom and kitchen outlets (outlets near water) too. These testers can be found for your type and voltage outlet, foreign or domestic, (like this one for the UK) at most home improvement stores, or even the electrical department at Wal-Mart. Use it to test all the outlets in the home and if a fault is shown, have it fixed by a qualified electrician.

 

[cucker tarlson]

It is important to understand that monitors are not "hot swappable". That is, monitors and graphics cards are not designed to have the cables connected or disconnected when the computer or monitor is powered on. It is quite possible you accidently caused a short by causing two wrong pins to come into contact with each other, causing permanent damage to the card, monitor, or both.

There is no solution for this - only a strong recommendation to stop doing that! Power off the computer and unplug it from the wall. Then securely connect the cable and leave it alone.

good to know cause I've done that a thousand times

 

[Bill_Bright]

Well, it should be noted, as expressed after I posted that, that HDMI is designed to be hot-swappable, as is Display port. But also as noted, it assumes the cables and connectors are not in need of repair. A friend who is also a technician pointed out he has hot-swapped video cables with no damage. However, he has frequently experienced resolution changes in the process. And with HDMI where audio was sent through the HDMI cable, the audio was lost. A simple reboot restored all, but shutting down whenever swapping cables is just a good habit. Then there is no need to remember what is hot-swappable and what is not.

 

[Jesus F]

The slight crackle as you plug in a power cable that’s connected to the mains is normal, yes. It’s caused by arcing, which should be kept to a minimum.

Ok got it thank you very much