Ultra Xfinity 600w 5vsb mod

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

Cool

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

i have since gotten the system's board to work... and when used, the 5vsb noise disappears. it IS a load related issue.

whew.

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

Get a straw and use it to listen to the power supply parts up close when its running, you wouldn't want to get shocked on the ear!

Is it actually a steady hiss, or an arcing sound? Could be a falied ceramic capacitor on the primary flyback voltage suppressor circuit. I have found out before that cheapo ceramic caps dont like voltage near their max rating.

I suppose it could be that you replaced the secondary caps with bigger ones too. I have noticed that, say, in 555 oscillator circuits, that a decoupling cap near the 555 makes the 555 output a slightly lower frequency than without the decoupling cap.

-Ben

it is like arcing...

the caps (other than the 5vsb) are same values, bigger physical size. the 5vsb caps were per what i was told shoudl be swapped... but since the cap order somehow got doubled, I have the caps needed if I wanted to swap the 5vsb caps back to the stock values.

[ben7]

Re: Ultra Xfinity 600w 5vsb mod

it is more like an arcing noise than a squeal come to think of it. almost like a hiss.

Get a straw and use it to listen to the power supply parts up close when its running, you wouldn't want to get shocked on the ear!

Is it actually a steady hiss, or an arcing sound? Could be a falied ceramic capacitor on the primary flyback voltage suppressor circuit. I have found out before that cheapo ceramic caps dont like voltage near their max rating.

I suppose it could be that you replaced the secondary caps with bigger ones too. I have noticed that, say, in 555 oscillator circuits, that a decoupling cap near the 555 makes the 555 output a slightly lower frequency than without the decoupling cap.

-Ben

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

It's probably feedback instability, which is often caused by either bad caps or just bad design. Someone who builds Power supplies (eg, Th3_un1qu3) would probably know more about how to fix it, but my guess is it's one of the small caps you didn't replace.

I doubt if it would really be arcing. I have a Delta-built Antec that makes an arcing/buzzing noise, but runs just fine. If it really was arcing it would fail pretty quickly.

i have a dead delta 200w microATX unit that does this too come to think of it. its a lot louder but then again, it is also dead.

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

It's probably feedback instability, which is often caused by either bad caps or just bad design. Someone who builds Power supplies (eg, Th3_un1qu3) would probably know more about how to fix it, but my guess is it's one of the small caps you didn't replace.

I doubt if it would really be arcing. I have a Delta-built Antec that makes an arcing/buzzing noise, but runs just fine. If it really was arcing it would fail pretty quickly.

[momaka]

Re: Ultra Xfinity 600w 5vsb mod

it is more like an arcing noise than a squeal come to think of it. almost like a hiss.

Ah ok. I think that's a different problem. The one and only PSU I had that made a hissing noise was a Bestec ATX-250 12Z. That one really stunk up my room when I tried to use it. I think one of the capacitors in it must have failed.

Anyways, since you changed your caps, then I don't think that's the problem. Even though you didn't change the very small caps on the secondary, that should be fine as they are running on a low voltage and it's unlikely to hear any hissing from them.

If anything, check the primary side - particularly look for long leads on neighbouring traces that look like they are very close together.

Disregard the noise? Impossible! It's REALLY, REALLY, REALLY annoying!

Yeah, I hate high-pitched noises too.
I can't hear my computers when I'm further than 3-5 feet away from them, though.

[mockingbird]

Re: Ultra Xfinity 600w 5vsb mod

Did you change every last cap?

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

Maybe you put one of the capacitors in the wrong way.

then why did it do that before the recap? no change audio wise.

[mockingbird]

Re: Ultra Xfinity 600w 5vsb mod

Maybe you put one of the capacitors in the wrong way.

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

it is more like an arcing noise than a squeal come to think of it. almost like a hiss.

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

Disregard the noise? Impossible! It's REALLY, REALLY, REALLY annoying!

[momaka]

Re: Ultra Xfinity 600w 5vsb mod

i loaded the 5vsb with an old abit BH6 i had... the noise persists.

Some PSUs just like to whine. Both the 200W Astec and the 185W Lite-ON in my computers produce a fairly loud squeal. Both of these PSUs have been running for close to 10 years now without problem, so I just disregard the noise.
In any case, if you're worried about your motherboard being killed by the 5vsb, just install a 5.1v to 5.5v zener diode across the 5vsb. If something goes wrong with the 5vsb and the voltage on 5vsb goes over the zener diode's voltage, the zener diode will short out and kill the 5vsb. Not a very neat solution, but at least your motherboard won't die.

[brethin]

Re: Ultra Xfinity 600w 5vsb mod

Try loading the 5v rail heavy to test (at least 15 amps) and see if the noise goes away, my guess is it will.

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

Did you replace -all- of the capacitors, including every tiny one? If not, then it could be that one of them is the culprit (assumming that the squeal was there before the recap). I used to have this issue with the Antec StupidPowers, where they would squeal even after replacing all of the major caps, but a complete recap (minus the primaries) seemed to fix it.

You should probably find out where it's coming from as well (use the old straw to the ear trick). It will be one of the coils, or the feedback transformer (probably the middle one).

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

Cool. Now you owe me the power supply. After all I did help you fix it Just kidding

Try it with some load. I had the same issue with those Widetech/Great Wall power supplies. They had a slight squeal with no load, but they were fine as long as I loaded the 5vsb and 12V rails, it was fine.

i loaded the 5vsb with an old abit BH6 i had... the noise persists.

i unglued some things (yucky yellow glue)... i wonder if something is rattling?

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

Don't worry. It took me ages to find the short on the rexpower.

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

Keep an eye on them once you have some more load. Those heat sinks are fairly chunky, so it wouldn't surprise me at all if the fans don't spin when the power supply is cold. If you do think it has problems, though, it looks like an add-on daughterboard, so scavenging one from another PSU slould be easy.

i do have a partial spare from a junked 550w ultra... but it is missing most of the circuit (much more basic)

once I get the board for the project in and i get it recapped, then I can put some REAL load on it...

ps- I still feel like a .

[c_hegge]

Re: Ultra Xfinity 600w 5vsb mod

Keep an eye on them once you have some more load. Those heat sinks are fairly chunky, so it wouldn't surprise me at all if the fans don't spin when the power supply is cold. If you do think it has problems, though, it looks like an add-on daughterboard, so scavenging one from another PSU slould be easy.

[ratdude747]

Re: Ultra Xfinity 600w 5vsb mod

Cool. Now you owe me the power supply. After all I did help you fix it Just kidding

Try it with some load. I had the same issue with those Widetech/Great Wall power supplies. They had a slight squeal with no load, but they were fine as long as I loaded the 5vsb and 12V rails, it was fine.

all i have for load is a dead sata hdd... and the 4 fans in the case. currently i have all of those running, no noticeale ripple on the analog meter. the voltages are also in spec.

oddly, the fans have yet to turn on... everell, the original owner, noted that the fans never turned on for him either... the stock fans were wasted, and i replaced them... either the thing hasn't gotten hot enough or the fan controller has issues.