Capacitor whining?

[Doomz]

I notice you have a 7800GT

 

I have a 7800GTX an it makes a variety of high pitch eletrical type humming noises etc.

 

I can often hear it and from what I gather it is more to do with the colors being displayed on screen than the ammount of processing that it is doing.

 

It makes these noises during the menu screen of Aquamark3 but not during the actual 3D part.

 

The other day playing the game BloodRayne2 it would buzz and hum if I moved the ingame camera angle close the the Rayne character, but if I zoomed out it would almost stop.

 

I also believe that certain screen colors make the 7800 buzz. When at certain webpages that are mostly a certain color it will buzz. If I alt-tab between pages it seems only to buzz due to a certain background colour.

[kryptonite514]

Just played COD2 today, such a good game. But when loading, I noticed that my computer is emitting a very distinc hissing/squeaking sound. It gets louder when the loading stops and says "Click Fire To Start"

 

Wanting to eliminate any chances of other variables, I ran the system 100% passive and loaded up COD2. Still makes that noise.. now I know its nothing mechanical... I noticed the noise occurs even when Windows is loading, and in Prime, anything intensive. I lowered my vcore down to 1.4 and the noise isn't as strong as it was before in the same scenarios. Upping the vcore (while still at stock speeds) did make the noise higher. I am going to up the MHz to see if it gets louder with that too. I did notice this noise earlier this week but it wasn't as loud.

 

I personally think a cap on my motherboard is slowly going.. but I don't know enough to actually say this. Does anyone else think this too? I highly doubt a CPU could make that noise? It IS happening on the top/right side of the motherboard. I did take a quick glance at the caps and everything looks alright.

 

I also talked to a friend with an SLI-D and he has the same problem...

 

I've noticed this as well. It sounds like tiny puffs of air or a mechanical noise. Actually it sounds like a small animal breathing, I dunno if any of you know what a sugar glider sounds like.

[MikalCarbine257]

ESD as in the anti static bags?

 

I checked to see if it was coming from the GT at all, and I don't think it is likely. Are the power inductors the metal coils around the ciramic disc? It sounds like its coming directly from that one near my ATX connections

 

Nail varnish, as in fingernail polish remover? Would rubbing alcohol work?

 

I might just get a new motherboard, RMA this one then sell the new one in box when I get it back. DFI Expert anyone? :nod:

[sluggo]

I would doubt that it's a capacitor making the noise. A ripple current large enough to move the plates in a cap will heat it up and destroy it in no time.

 

The "singing" you hear is the wire on the inductors rubbing against the cores that they are wrapped around. Yes, the wire actually moves. The effect is like the water hammer that you can sometimes get in your water pipes, except in this case it's caused by starting and stopping a large DC current 100K times per second. The larger the current (as when you boost the voltage), the larger the effect.

 

It's usually benign. If the wire isn't wrapped with the right amount of tension it will find a way to rub, but the electrical performance is unchanged.

 

Inductors used in this sort of application are sometimes "potted" in epoxy to prevent the noise.

 

EDIT: JUst read prjkitch's post. Ditto what he said about the varnish. Superglue (cyanoacrylate) works as well.

[SageI]

Thats why I was banking on the power supply.

 

A switching power supply steps up the 60 cyc coming in to it to around four hundred cycles wich is passed threw the primary transformer before rectifying it back down to DC.

 

By this means most of the current is passed in voltage (meaning that all components can be smaller) before being rectified down to DC.

 

Which gets a added benifit of being recitified at 400 AC verses 60 AC which means that the generated ripple is much less.

[jimmil43]

Damn that alomost makes sense, I was wondering wht switching PS's were so much smaller. Just never bothered me that much.

[MikalCarbine257]

Nail varnish? As in nail polish or remover? If polish, what color :shake: :nod:

[sluggo]

Thats why I was banking on the power supply.

 

A switching power supply steps up the 60 cyc coming in to it to around four hundred cycles wich is passed threw the primary transformer before rectifying it back down to DC.

 

By this means most of the current is passed in voltage (meaning that all components can be smaller) before being rectified down to DC.

 

Which gets a added benifit of being recitified at 400 AC verses 60 AC which means that the generated ripple is much less.

 

Sort of. The 60 Hz AC from the wall is first boosted via a transformer, then rectified to yield 400 Volts DC, which becomes the bulk supply for the rest of the power supply. There are no 400 Hz AC signals in the supply - as for the size of the magnetic components, 400Hz is not all that much different than 60 Hz. The secondary supplies switch at much higher frequencies, on the order of 20kHz.

 

My strong suspicion is that it's not the system power supply, but the inductors on the regulation circuitry on the motherboard. These are the supplies that take current from the system power supply and convert it to the voltages required by the processor, memory, etc.

 

Don't use nail polish remover - it's acetone, which will remove the insulation from the inductor windings. You would not like what happens if you do that. Use a clear polish ... you can use a color if you like, but the clear polishes tend to go on heavier and make a tougher coat.

[MikalCarbine257]

I am just RMAing the board, I don't want to void any warranties of any sort, better safe than sorry, and I have a reason for a slight upgrade

[Slammin]

Since you are certain it is not your PSU (90% of the time it is), then my money would be that is is your vid card. Go to any vid card forum and you will find that the 'singing' is quite common.

 

Sometimes, just powering your vid card from a different, and preferably, a power connector that is not shared with other devices cures it.

 

edit: and though you didn't mention if you had one, but a lot of fan controllers that use PWM (Pulse Width Modulation) to control fan speed, will sing/buzz with certain fans.

[MikalCarbine257]

I don't have a fan controller :S

 

As for the seperate connector, I am using the stand alone PCIe connector from my OCZ 520w, the one that is coated to reduce interferance and such

 

If I have time I can try a different video card

[SageI]

I was going to leave it alone but I can not.

 

sluggo:

 

The voltage is stepped up to 400 V and is DC how ever this DC is then chopped at 400 cyc making a square wave .

 

This square wave is passed thru the power transformer which is tune to 400 cyc.

 

The result on the secondary is a perfect sign wave do to the reluctance of the transformer.

 

The secondary is tapped for the various voltage required for the output.

 

All the secondary has tied to it are full wave bridges that rectify the voltage to DC and then filters it threw a pi or invert L filter network.

 

There are 2 factors that keep the power xformer small:

 

A toroidal xformer is used which couples lines of flux much more efficiently than a slotted E xformer.

 

At 400 cyc the transformer can be smaller.