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 Post subject: Coil Whine
PostPosted: Sun Feb 02, 2003 12:50 pm 
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Location: Olympia WA USA
Yes, apparently my Antec (HEC OEM) PSU is exhibiting a very bad whine on idle, but not load :roll:. So I got myself a bottle of brush-on superglue, but I'm not sure which coils I should apply it to.

Image

Are the coils with the black and yellow cores the proper ones to apply the superglue to? Or are there others I should be looking for?

EDIT: If I'm not mistaken, the yellow wrapped objects are transformers. Knowing that tranformers have coils inside of them too, are these the ones I'm shooting for that would be making the noise? If so, I will probably end up just getting a new PSU.


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 Post subject: Re: Coil Whine
PostPosted: Mon Feb 03, 2003 3:44 am 
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Bad high pitched whine isn't coil whine, it is chopper regulator. You might try to replace capacitors with new ones, but if this doesn't help then this psu is just badly designed and can't be easily fixed.


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 Post subject:
PostPosted: Mon Feb 03, 2003 3:15 pm 
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So there is no way to fix it except by replacing the capacitors?


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 Post subject:
PostPosted: Tue Feb 04, 2003 2:36 am 
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I read that it was better to use something that dried slowly so that it could soak into the coil better, like varnish. There's a product for TVs called "corona dope."


Last edited by larrymoencurly on Wed Feb 05, 2003 2:47 am, edited 1 time in total.

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 Post subject:
PostPosted: Tue Feb 04, 2003 11:01 pm 
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Well this is going nowhere. I was hoping that the contest would pull more people in and therefore relate to quicker responses, but I am going to have to do this soon, and still no conclusive answer on whether supergluing the yellow objects (transformers?) and the exposed coils will help anything. I am also planning to subsequently replace the 80mm fan in my PSU with a quiet NMB one, and remove the 92mm fan. But are these mods worthwhile in the first place, because the grating whine cannot be reduced at all?

It's all a cost/benefit comparison for me...I can either buy a new Seasonic PSU that will be about as quiet as the mod I plan to do to the PP-352X for $42, or do the mods for a grand total of about $4. I do not mind having to dig around in my PSU a bit, but seeing as I'm quite busy, if this turns out to be unsuccessful in silencing the whine, I would really rather not. So...anyone else want a go? :)

For the reference, yes my PSU is whining very loudly on idle, and quite discreetly, but still audibly, on 100% CPU load.


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 Post subject:
PostPosted: Tue Feb 04, 2003 11:44 pm 
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Search around in the forum. There are a couple of long threads on this topic and it is not superglue that's recommended. Can't recall the name of the stuff...

The other thing is that if it is making that much noise, it seems to me you have a legit reason to get the PSU replaced under warranty. It does not sound normal.


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 Post subject:
PostPosted: Wed Feb 05, 2003 12:18 am 
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I have already done a thorough search, and while finding useful threads on coil whine specifically, I did not find anything that would pertain to my current situation, namely, where would I apply the adhesive in the first place?


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 Post subject:
PostPosted: Fri Feb 07, 2003 7:54 pm 
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Ah! It seems the noise was coming from the 80mm fan in the PSU after all! :oops: :lol: Even though I saw no control circuit while poking around in the PSU, there obviously must be something affecting the fan speed during idle vs load. So...any good fan replacement choices? Besides the obvious Panaflo L1A of course. :)


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 Post subject:
PostPosted: Sat Feb 08, 2003 11:53 am 
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Hmmm....How about a 7-volted M1A. :D

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 Post subject:
PostPosted: Sat Feb 08, 2003 1:19 pm 
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MikeC wrote:
The other thing is that if it is making that much noise, it seems to me you have a legit reason to get the PSU replaced under warranty. It does not sound normal.

Alas, the warranty was voided once he cracked open the PSU... bloody warranty stickers!

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 Post subject:
PostPosted: Sat Feb 08, 2003 7:10 pm 
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Gah, you people are no help. :D I was thinking of something along the lines of a NMB 18CFM fan. Would this provide enough air for the task?


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 Post subject:
PostPosted: Sat Feb 08, 2003 8:28 pm 
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18 cfm will be about half the rated airflow of the original fan. It might not be enough depending on what the fan control circuit does in that PSU. It would be nice to know what the fan voltage is at idle vs max load. If you have good cooling airflow for the rest of the case/components, it might do.

One question is what you're actually hearing -- ie, why would the fan whine at idle and not under load? Is it that the fan bearing is going? Often, worn or damaged bearings make more noise at lower speed than at higher.


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 Post subject:
PostPosted: Sat Feb 08, 2003 10:40 pm 
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There must be some sort of fan control device in my PSU even if I didn't see one, for the whine of the fan certainly changes in amplitude depending on load. It could indeed be that the bearing is shot and exhibiting the exact behavior you mention. I have heard that a PWM circuit can also cause unnatural modulations in the fan coils, which might also cause a whine. Whatever the cause, all I know is, this fan has to go. :)

Also, after stopping all the fans in my system except for the other 92mm fan in my PSU there is a sort of "rattling" noise going on in my system, indicating that that fan might be on its way to the graveyard too.

What I plan to do is take out the 92mm fan, tape up that vent, and replace the 80mm unit with the 18CFM NMB fan so that the air will be pulled in from the back and flow directly across the components in the PSU. I will also have another 18CFM case fan exhausting air from the back, and will replace my current Volcano 7+ heatsink, which exhibits some fan vibrations and is quite loud even on "low", with an Artic Cooling Super Silent 4 TC. Additionally I have already unplugged my Radeon 8500's wimpy fan (doing fine so far with the airflow of the exhaust fan over it) and have a Maxtor FDB HD, whose noisefloor is nearly that of the Barracuda IV (that is to say, nearly inaudible, even in standard mounting configuration). How does this setup sound to you?

EDIT:

Just to get some thoughts jumbling around in my head down...

First, what is the "static pressure" measurement for fans? And which is better, higher or lower? (in terms of airflow/noise) For example, the L1A has a SPR of 1.57mm-H20, while the NMB has a SPR of 0.07in-H20.

Second, my PSU seems to have especially small heatsinks. Would this be a major problem if I used a low CFM fan?

Lastly, should I leave the bottom 92mm fan vent open or closed (in regards to CPU/PSU temperature) considering that the back vents are quite small?


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 Post subject:
PostPosted: Sun Feb 09, 2003 3:23 pm 
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Er, does this sound alright (sorry if it sounds like I'm being pushy, but I've got to get the stuff today or tomorrow to get it here in time)?


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 Post subject:
PostPosted: Sun Feb 09, 2003 3:36 pm 
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No guarantees. It's mostly trial & error if no one's reported about modding that same PSU. Sound's like you're going to do it anyway...

Don't worry about static pressure -- if you change the voltage, that'll change too, anyway.


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 Post subject:
PostPosted: Mon Feb 10, 2003 7:32 am 
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I'm sorry if we don't sound very useful... whether or not a PSU mod will do well is very particular to the system you are on. Plus, I think most of the people here are pretty fearless when it comes to mods... I know I would have just coated that sucker in glue on the theory that glue is nonconductive anyway. :)

We're explorers. There are ideas, but nothing written into stone. I doubt anybody is going to give you the hard and fast answers you seem to be looking for... The best thing you can do is to make the mod, and add to the pool of knowledge.

To try to address your questions: I ran a 150W PSU with a 5v L1A fan with no problem for 2 years, and now am running a 300w Verax with a thermally controlled L1A that has yet to exceed 5v. If you are worried about cooling power, and keep your CPU in a hot room, drop in a M1A or a (gasp) H1A. But really, your PSU will probably happily chug along with a 18 CFM fan, especially with thermal control. If you find it maxes out for long periods of time, try dropping in a higher airflow fan.

Small heatsinks are the bane of all that is good and pretty. That being said, it is probably not a problem. Like I said, I ran a low flow fan on a cheapie for a long time without a problem, and that PSU must have weighed 1 lb at most. If you can swap out the heatsinks and have the time, it would be a fun project. But I wouldn't worry too much about it if you're feeling stressed.

As for the 92 mm hole... I can't make a strong recommendation. You want to maximize the amount of air that can get through the PSU, but you also want to make the air flow through the components properly. As a guess, I would also tape up that hole, and would open more space in the back with a dremel... probably making a 80 MM hole and covering it with a grill for EMF shielding. But the stock holes might be large enough for a low-flo fan... You can tell if it needs modding by the noise the fan makes. If it sounds loud for the voltage, add more holes.

I hope this helps! Keep us posted!

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 Post subject:
PostPosted: Mon Feb 10, 2003 5:57 pm 
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Thanks for the excellent reply Chris! I think I will just "go for it" then, shall I? 8) I'd imagine with a 18cfm fan, there won't need to be very many holes considering how little air it pushes. It'll probably just come down to experimentation, covering up various amounts of the 92mm intake. Now to order...:)


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 Post subject:
PostPosted: Fri Feb 14, 2003 11:35 pm 
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larrymoencurly wrote:
I read that it was better to use something that dried slowly so that it could soak into the coil better, like varnish. There's a product for TVs called "corona dope."


A question before I do something unwise: my PSU whines, I'm not sure if it's the coil or something else. As such, would it be safe if I just spray insulating varnish over various parts of the PSU, or is this risky? Thanks.


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 Post subject:
PostPosted: Sat Feb 15, 2003 4:14 pm 
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I wouldn't use spray varnish because spray paints contain solvents that can attack plastics, like the insulation on the wiring. Try any coating on some styrofoam first -- I learned that spray polyurethane woud dissolve it, but brush-on wouldn't. Also spraying probably wont' help cut any whine because you want the coating to really soak into the windings. I've read that manufacturers use a vacuum chamber to remove all the air bubbles, then they pressurize to force the varnish in.


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 Post subject:
PostPosted: Sun Feb 16, 2003 4:21 am 
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So the copper coils are the things that whine?


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 Post subject:
PostPosted: Mon Feb 17, 2003 2:20 am 
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I don't know for sure, but I think the copper coils are much more likely to whine than the core because the coils are so much lighter, and I've read of technicians silencing coils and transformers by coating them with varnish or "corona dope" (made for prevention of high voltage arcing) or wedging toothpicks or cardboard between coils and cores.


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