Seasonic PSU making a tiny buzz noise

[sokos]

I got this case that came with a 350W Seasonic SS350-ATC Active PFC and when the PC is switch off (mains is plugged in) it makes a thin buzzing noise that u can here quite well if you stick your ear next to the PSU.

Do you think is this bad and I should return the case (coz this will be a Small Server machine very important to my work) or it's nothing to worry about ?

Thanks!

[Galvanized]

Re: Seasonic PSU making a tiny buzz noise

"I got this case"...Does that mean it's new? If so, to be happy, you might contact Seasonic for an answer or RMA the case w/the PSU to the vendor.

With the cover off, on the bench, some PSUs will make a very faint whine when powering down. It has to be real quiet for my old ears to hear it.
I'm not an expert on this, as I've only had several open on the bench.

User name at another forum, ENERMAXPM(Product Manager) was asked about the zing the Libertys(500W or more) make when powered up. He started it was normal and is called "transformer ignition". The windings take a jolt, get excited and produce a noise.

With your Seasonic it might be just normal operation. When ppl strive for the quietest possible rig, all kinds of normal noises get noticed.

[gonzo0815]

Re: Seasonic PSU making a tiny buzz noise

I have only experience with the Ss300FS and 400FS, and both have problems with the 5v stand by power unit. The problems are bad caps in this section. I have replaced those in a few SS400FS and they are new. I think the desing of those Seasonic PSU`s are not bad, and therefore worth to buy and replace those caps as standard procedure.
As i learned from a member here, those caps should replaced with some 1000uf low esr caps, not more.
In any way i have replaced those with 1500uf and it seems to bee long therm stable.
If you are under waranty, RMA it and buy something other or repair it. I suggest a seperate PSu e.g the S12 OEM lines SS300HT or FT.

[sokos]

Re: Seasonic PSU making a tiny buzz noise

ok I think I found out what the problem was!
I used on the same power outlet with the PC a big lamp of the room which has a dimmer on it. Once I plugged off the light, the buzz dissapeared!

[gonzo0815]

Re: Seasonic PSU making a tiny buzz noise

This is somhow obvious, any dimmer will produce some EMI and this could lead to some oscilaton in the EMI filter of the PSU. But if the nois will come back without the dimmer, a sound like some arcing then remeber my above post ;-)