FSP 350PN high pitched sound

[elod]

Just bought a 350PNF. Really cheap, expected somewhat bigger rectifiers on the output side. Don't know what they are, because you can't see them (and i don't want to void the warranty - yet). The unit is not sealed, so you can open it up without losing it.

There's one big, no, Huge problem with it. It constantly emits a high pitched noise (whine, really). It's not the fan, i stopped it. It's electronics. Could be a cap. Caps are cheap (OST 680u/200V, Teapo & OST on output, nothing really small or really big: 2200u, 3300u).

There's one other guy who noticed it (search google for 400PN high pitched).

Did someone else notice this (maybe with other psu)? It's driving me craaazy.

[gonzo0815]

Re: FSP 350PN high pitched sound

Probably one of the coils, either the PFC coil or the one in the output filter. I doubth that there is mutch to do than either using some glue or buy an non or A-PFC unit.

[elod]

Re: FSP 350PN high pitched sound

Passive PFC is really easy to remove. I'll open it up once more and try to locate the source.

Heatsinks are really small, so i tugged a thermocouple in between. 40 C, under load (A64 Venice, 2.4Ghz, GF62000 - yeah, pretty lame).

[Spacedye69]

Re: FSP 350PN high pitched sound

Not that this is any help, but I have a similar problem on a Lite On made Dell psu. The whine starts when I plug it in, and stops after what seems like a cap discharge, slowly going down in pitch, after I unplug it. Caps look ok, but it is pretty old. All UCC and Pubycon from what I can see.

[tiresias]

Re: FSP 350PN high pitched sound

All UCC and Pubycon from what I can see.

[Spacedye69]

Re: FSP 350PN high pitched sound

LOL

[elod]

Re: FSP 350PN high pitched sound

Not that this is any help, but I have a similar problem on a Lite On made Dell psu. The whine starts when I plug it in, and stops after what seems like a cap discharge, slowly going down in pitch, after I unplug it. Caps look ok, but it is pretty old. All UCC and Pubycon from what I can see.

Mine is dead silent in standby. It starts when i push the damn button. Today I saw an enermax doing the same thing. And the owner doesn't even notice it. In 10 years maybe I won't hear it anymore.

I've got to check the discharge thing. Even stanger is that I did not notice the noise when it sat before me.

Tomorrow is psu hacking day. Again. I've got an Antec to service (my first repair - i hope), I know it's not worth it (SmartPower SL350), doing it for experience .

[elod]

Re: FSP 350PN high pitched sound

Mine is dead silent in standby. It starts when i push the damn button.

Apparently it's NOT. And it's not the passive PFC. It seems to be the stand-by transformer. When I measure the voltage on the big diode nearby the sound changes in pitch. The same thing happens when I start start the unit.

Just as Spacedye69 said, it goes away slowly (discharge) if i pull the plug.

Damn PSU makers. They can't even buy a decent enough transformer. The 3 main transformers are labeled "DASH 2 B-5". Don't know if that specifies the manufacturer, but I want them to suffer .

Has someone got a recent Fortron to confirm the noisy stand-by transformer?

[tiresias]

Re: FSP 350PN high pitched sound

Has someone got a recent Fortron to confirm the noisy stand-by transformer?

Hi Elod,

Yes, one of my kids' machines uses a slightly older FSP-300PN (PF) model, and it does have a small degree of buzzing. It is very quiet though, hardly something you would notice unless you were to place your ear very close and really listen out for it.

I had always assumed it was the large passive PFC coil, but now that you mention it - you could be right about it being the transformer for the +5Vsb line.

All small ones are marked DASH-something indeed. The main one reads "SPI..."

[elod]

Re: FSP 350PN high pitched sound

Hi Elod,
All small ones are marked DASH-something indeed. The main one reads "SPI..."

On the side of the transformer "SPI 8TC00206". This is the small one (stand-by). The big one is "SPI 8TG00212". DASH is on the last line, don't know what it means.

Well, I can hear it from across the room. Not when it's in stand-by, but when it's on. It's definetly not the PFC coil. I removed it, listened to it while on, it's completely silent.

Thanks for replying. At least I know that it's not just mine.

Tips for another, SILENT & cheap but reliable PSU? I really liked this one, because it's really cheap, and I don't want to invest a fortune in another psu, after 2 antecs caused me trouble (one exploded, the other one had one leaky Fuhyjuu cap).

[tiresias]

Re: FSP 350PN high pitched sound

Tips for another, SILENT & cheap but reliable PSU? I really liked this one, because it's really cheap, and I don't want to invest a fortune in another psu, after 2 antecs caused me trouble (one exploded, the other one had one leaky Fuhyjuu cap).

Well, as you can probably see from this section of the forum, one could talk forever about the ideal PSU for an particular situation.

Personally, at the moment I would recommend (if you're willing to spend over $100), one of the Etasis-made Silverstone-marketed models, such as the ST56ZF. The ST75ZF is more expensive, but you only have to look at its components, specifications, and also importantly, PCB layout, and you'll see that it's in a class of its own.

In the more affordable (sensible) range, which I think is what you're looking for, I've always been quite pleased with the Enermax-branded units. If you take a look at their "noisetaker' series, they should make a 325W, or 375W rated model for a good price.

[PeteS in CA]

Re: FSP 350PN high pitched sound

P/S mfrs usually design and build their own transformers. Most SMPSs switch at 25KHz or higher, and should not be audible. The exceptions I've heard have been where the P/S was in current limit or was oscillating due to a design goof or a wrong componet was used. One recent exception to this with which I have no experience is regulator IC that reduce the switch frequency to improve efficiency at light load or when operating in standby mode. I realize that this doesn't accord with the experiences of many folks here.

[Shroomie]

Re: FSP 350PN high pitched sound

the Enermax-branded units. If you take a look at their "noisetaker' series, they should make a 325W, or 375W rated model for a good price.

Ditto. I have the 420 - haven't opened it up yet, I know some of the smaller caps are the mediocre jPce TURs, but I'm not too concerned. It seems like a good quality unit, fairly heavy, and is basically silent. I'd recommend one.

I've heard great things about Silverstones, too. Cost is high, but arguably worthwhile.

It's really sad to see Fortron/Sparkle go downhill like this - the Fuhjyyu caps were bad enough. Sharp contrast to their older models, heavy 200-watters from '98 and '99 with all Chemi-Con caps. Decent fans, too.

[kc8adu]

Re: FSP 350PN high pitched sound

check for loose cores in the transformers/chokes.
i have seen a few that were loose that would annoy me enough to pull out dr. glock and shut it up.
ca can be squirted in and hit with zip kicker.

[elod]

Re: FSP 350PN high pitched sound

Nothing seems to help. I've poked around many times, with a rubber-ended pencil, no loose cores, no change in the annoying noise.

I've been to the shop today, and listened to another one, it's the same thing. Unfortunately they did not have a Greenline, so I couldn't check that series.

I'll buy a greenline & a seasonic S12-430 for two new builds, just to see how they compare, and if any of those makes strange sounds.

[gonzo0815]

Re: FSP 350PN high pitched sound

Think both a great units, IMHO all A PFC, wich means no big PFC inductor. I think they should suite your needs, especially the Seasonic one.