humming sound from computer.

[Lysix]

this computers just cursed with goddamn problems. although this one isn't stopping my useage of the pc (yet) its pissing me right off.
the pcs humming. i take the top cover off, it stops for a bit, then comes back. i take the side covers off, it stops for a bit then comes back. although without the covers it goes from an erratic buzz to a lovely humming sound.  it fades in, then fades away and repeats.

at first i thought it was the harddrives, so i removed them and refit them. no result.
then i thought it was the extra fan, so i turned it off as it wasnt nessecary. no result.
then i thought it might be the motherboard fan, so i rid the bastardised thing of all dust. no result.

I HAVE NO IDEA WHATS CAUSING THIS AND ITS REALLY GETTING ON MY TITTIES ]:

[Jack Lupino]

used to have the same problem, it went away if i just smashed the pc with my fist (most of the times)
but on 1 day the pc broke so now i have a different one.. wich just randomly reboots as it sees fit.. -.-


Dust could be a problem causer in this

[Bocom]

Aah, computers.

Fscks with you every chance they get.

[Ankle]

Buzzing/humming sounds are common from inverters and often it can be no sign of a problem - just very annoying. For instance most LCDs have an inverter than I can hear buzzing that most people do not notice over ambient noise and it drives me absolutely bat shit insane. It could also be the bearings going in a fan, but that is usually more of a rattling sound.

[evilcandybag]

Even though you may have refit your HDDs, it may still be them making the sound. Just because your retailer (or you) fit your HDDs in a way that works, it doesn't mean they'll not sound annoying. Getting a HDD rack with lots of sound dampening might help a lot compared to your normal stuff.

[SweZor]

Do this:

Try it without the HDD's power plugged in (the rest of teh computer will run)
Try without the CPU fan power (this is okay for a few minutes, tops, just to see if it sounds any better)
Also try without DVD drives and graphics card (if it has a fan on it)
As long as the motherboard has power, the computer will turn on, so you can pretty much unplug everything to see if it sounds better.
If it still sounds bad, it might be the PSU or as Einkoro says, an inverter.
If that's the case, there's not much you can do save getting a new part.

[Kernel]

Reasons for my computer humming used to be:
broken Fans
vibrating DVD drive in combination with loose side covers. Especially when the drive was not at full speed, but spinning the disc slowly but constantly in "idle" mode...
a funny ground loop
and at the moment, it hums slightly when the dynamically clocked CPU goes up to full speed. I guess that's the power supply dealing with the higher current. It used to hum constantly when the old CPU and mobo were still in there. But that was barely noticable when the case wasn't open. I do notice it now, but I think that's only because it's not constantly there anymore. And as I said, it's very quiet, far from annoying.

[Lysix]

gonna try taking components out one by one and try track the problem down. ive taken the side panels and top panel off, and the buzzings subsided. so ill keep it like that for now.

[Kernel]

I guess your PC is vibrating slightly, and the panels on the sides start to vibrate as well, amplifying the noise. Try stopping them from vibrating by fixing them tightly to the base of the case, with tape or something, or put something into the gap between the base of the case and the side covers, maybe that will help...
Or just leave them off, if it doesn't bother you

[PrescriptiveBarony]

the case isn't meaningless though, as it acts as both a dustshield and faraday shield... so try not to generate too many electrostatic fields with it off.

[Kernel]

And don't forget, if your PC is standing on the floor, it prevents you from accidently kicking your graphics card

[Lysix]

okay, so i took out the power from the harddrives, cased it back up and turned the PC back on.
bingo. no humming sound to speak of. just a nice quiet fan sound.
so now i've narrowed it down, what exactly can i do? ive screwed the harddrive screws in as tight as possible, i really dont understand whats causing the vibrations!

[Kernel]

Well, the drives may vibrate slightly, and the frame of the case will vibrate with them. So some parts of the case may hit other parts causing the noise. Maybe you find the buzzing/humming part and fix this one more tightly.

Or maybe it helps if you fix the hard drive in a different place. Or get a pack of those hard disk holders with rubber in them, whatever those are called. When it's held by those, the drive can vibrate, but the vibration isn't tranmitted to the rest of the case.

[SweZor]

Try to have the HDD turned on, but not attached to the case, that way you see if it's the harddrive itself vibrating, or just making a noise from within itself.

If it's vibrating, you should try and dress the sides with thin rubber stripes, so it doesn't have direct contact with the HDD rack, that way vibrations won't transfer into the case.

If it's teh HDD itself making the noise, you'll have to get a new HDD, or simply live with it.

[gaijin]

Try to have the HDD turned on, but not attached to the case, that way you see if it's the harddrive itself vibrating, or just making a noise from within itself.

If it's vibrating, you should try and dress the sides with thin rubber stripes, so it doesn't have direct contact with the HDD rack, that way vibrations won't transfer into the case.

If it's teh HDD itself making the noise, you'll have to get a new HDD, or simply live with it.

There are rubber-suspended cases (with cooling) that are sound-dampening as well, if it's the drive itself making the noise. Haven't tried 'em myself though.