Eliminating PSU coil whine using silicone - need HELP!

PSUs: The source of DC power for all components in the PC & often a big noise source.

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tay
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Eliminating PSU coil whine using silicone - need HELP!

Post by tay » Fri Mar 26, 2004 11:54 am

Hi,

I have read somewhere in these forums that silicone (the caulking gun stuff)
- an insulator
- a dampener

Someone also suggested using it on the MOBO power coils. Would it be possible to use silicone in the PSU to try and dampen the coils causing the whine? I suppose Electricians goop (that yellow stuff) could be used but it is hard and permanent (You can get removable silicone that peels off in case it doesnt work).

Would possible high voltage in the psu cause hazards for using the silicone? Or is it safe using judiciously on the coils alone.

IIRC my PSU (cheap fortron model) has a rubber sleeve tightened over the coils (but it doesnt seem to help much as I definitely have some coil buzz).

I'd love to hear some informed opinions before actually trying it out.
cheers

CallMeJoe
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Post by CallMeJoe » Fri Mar 26, 2004 12:01 pm

Should be no problem. Use a high quality RTV (GE, Dow Corning, etc.) instead of tub & tile or caulking. Check at auto parts stores if your local hardware doesn't have the good stuff. Use just enough to bond the wire to the ferrite and dampen the whine, don't glop it all over the coil.

al bundy
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Post by al bundy » Fri Mar 26, 2004 3:52 pm

CallMeJoe wrote:...Use just enough to bond the wire to the ferrite and dampen the whine, don't glop it all over the coil.
Just curious, what would be the risk if the coil did get "glopped"? Is it dangerous, etc?

:?:

CallMeJoe
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Post by CallMeJoe » Fri Mar 26, 2004 5:20 pm

Silicon sealants emit acetic acid as they cure. If you completely cover the coil in sealant, there is no way for the acetic acid next to the coil wire to dissipate. It can eat the lacquer the coil wire is coated with, leading to a shorted (or partly shorted) coil. While this won't keep the coil from conducting, it will change its inductance and thereby the characteristics of the filter circuit it is part of.

al bundy
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Post by al bundy » Fri Mar 26, 2004 9:10 pm

Interesting! Thank you.

8)

tay
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Post by tay » Sat Mar 27, 2004 10:44 pm

Thanks Joe!!!
I didnt even know they were called silicone RTV's. Anyway, I googled a GE FAQ and they claim they have versions w/o the acetic acid now (although I'm not yet sure how to figure out which ones do, I'm guessing most do have acetic acid). I'll do more digging to find out.
I'll try this next week for sure. I have some reports to hand in so cant risk killing a psu. Thanks again for sharing your knowledge.

MysticX23
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Post by MysticX23 » Sun Mar 28, 2004 1:56 am

post pics if you do try this! i'd like to see how its done too. =D

CallMeJoe
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Post by CallMeJoe » Sun Mar 28, 2004 12:44 pm

tay wrote:Thanks Joe!!!
I didnt even know they were called silicone RTV's. Anyway, I googled a GE FAQ and they claim they have versions w/o the acetic acid now (although I'm not yet sure how to figure out which ones do, I'm guessing most do have acetic acid). I'll do more digging to find out.
I'll try this next week for sure. I have some reports to hand in so cant risk killing a psu. Thanks again for sharing your knowledge.
"RTV" for "Room Temperature Vulcanizing". I would guess the "aquarium safe" silicon may also be acetic acid free, but I would stick with electronic grade for heat and fire resistance (also a possible concern with tub & tile or caulk). As long as there is a path for the acetic acid to disperse, I wouldn't worry about degrading the coil insulation.

dukla2000
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Post by dukla2000 » Mon Dec 20, 2004 9:14 am

Apologies for dragging up an old thread, but came across an interesting approach to silencing buzzing components that allegedly works. I know this has been discussed a couple of times - I have posted my failures with toothpicks and epoxy glue at least twice.

Check out the "flood with wax" technique at Phoronix.

teejay
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Post by teejay » Mon Dec 20, 2004 2:07 pm

Sorry, just had to post this to point out that there are other types of computers users/modders out there:
Phoronix wrote:What do you do when something is too hot? Strap the fastest and loudest fan you can get your hands on, that's what to do. We settled on a nice clear 100CFM fan with blue LEDs. To power the fan, we tapped into the 12V and ground rail.
Yep, that's the first thing that would spring to mind! And no undervolting the sucker... can you even buy 100cfm fans without a license? Or do they come with "hearing hazzard" labels? :lol: :lol: :lol:

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Post by pangit » Mon Dec 20, 2004 4:01 pm

Interesting idea. I suppose this should work with buzzing CRT monitors (remember those? :wink: ). I've got one which buzzes occasionally, but I have't opened it up to see what the culprit is. I'm a bit worried going anywhere near those scary voltages.

Has anybody tried it sucessfully?

pdf27
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Post by pdf27 » Tue Dec 21, 2004 1:19 am

teejay wrote:can you even buy 100cfm fans without a license? Or do they come with "hearing hazzard" labels? :lol: :lol: :lol:
Yeah, I've got a couple for my next build. They're actually no noisier than my PC used to be before I started silencing it, and undervolted they're the quietest fans I've ever heard. Then again, some fans are more equal than others...

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