If you're looking for a solid 550W PSU, check this out.

[PCBONEZ]

Re: If you're looking for a solid 550W PSU, check this out.

For that matter if you add say a 5 amp 12v->5v between those rails inside the PSU you will beef the 5v rail up by 25watts.

[gdement]

Re: If you're looking for a solid 550W PSU, check this out.

Interesting idea.
As an experiment, I tried unplugging both the drives. Unfortunately, the reported 3.3V readings only improved slightly, something < .02V. (.02V is the resolution of the reading, but it spends more time at the higher number now)
So I'm not sure it's really a problem with the overall 3.3+5V wattage, maybe the 3.3 alone is just getting hammered.
I'll have to look into the regulator idea some more. Maybe there's regulators that go 12->3.3V ?


I noticed a weird noise from the power supply when I was unplugging the drives. As long as the PSU is plugged in, it makes a periodic buzzy scratching sound, repeating at a rate of about 4Hz. With the motherboard plugged in, it speeds up. With the motherboard actually booting up and running, it turns into a continuous buzz. I only noticed it when I got close to the thing.

[PCBONEZ]

Re: If you're looking for a solid 550W PSU, check this out.

Looking at the data plate for that in the previous post there is a third 12v rail at 8 amps.
You could easily use that for the input to a 12v->5v regulator.

Noise sounds like a loose winding in a transformer or coil.
Not sure why it would change speed though.
Does the fan speed up and slow down at about the same time?
Might wanna also look for arcing somewhere in there.

[gdement]

Re: If you're looking for a solid 550W PSU, check this out.

Yeah, that 3rd 12V rail looks like something I really don't need, so if I do a mod I'll probably take that and do the internal mod you suggested. I don't think the drives alone amount to enough amps to really solve the problem. The 5V rail seems to be doing okay though, it's just the 3.3 that's suffering, so I'm more inclined to tie it into the 3.3 output.

Does the fan speed up and slow down at about the same time?

I'm not sure about when powering up, but when I just plug the board in (for standby) the noise speeds up a bit and the fan of course still isn't running at that point. It gives me the impression that it's related to load.

[davmax]

Re: If you're looking for a solid 550W PSU, check this out.

There seems to be an unaddressed problem. Why is the 3.3V pulling so much current or is it? You need to get hold of a clamp ammeter and measure the current going into the mobo on the 3.3V lines. This should shed more light. You seem to have an ordinary mobo setup so why this problem? Compared with some PSU's the 3.3V current ratings you list are generous.

[Azurael]

Re: If you're looking for a solid 550W PSU, check this out.

I'd love to buy a couple of these PSUs for spares (and so I can re-cap the Hiper in my main rig), but it seems they don't ship outside the US

[PCBONEZ]

Re: If you're looking for a solid 550W PSU, check this out.

Davimax has a point.
Thoughts:
The AcBel as more amps on 3.3 than the Hipro.
Beyond what the motherboard itself uses most 3.3v goes to add-in cards.
5v normally goes to Mobo, add-in cards, memory, drives, keyboard/mouse/USB?.
.
The combined 3.3 + 5 rating is because they use the same transformer winding so if you are maxing out the winding thru either 5v or 3.3v it may affect either 3.3v or 5v.
It might be good to beef both 3.3v and 5v (more to the 3.3v) a bit with the excess 12v amps available.
[Ideally what you want to achieve is both of them loaded to the same % of their capacity. - Balanced loads.]

I got thinking about secondary cross-rail regulator because I'm having trouble find an affordable (I'm not so rich these days.) PSU for a particular system I'm trying to get together. It's a P4 server that will eventually spin 6 hard drives. Minimum I need for the power budget is 19a @ 3.3v, 27a @ 5v (~200w combined) and ~20.5a on 12v. (~246w). I prefer to over shoot the minimum by at least 15% on each rail so the PSU isn't normally tasked over 85%. (An keep them balanced.)
That puts me looking for around 21.5a @ 3.3v, 30.6a @ 5v (~224w combined) and ~23.4a on 12v. (~280w)
- Finding enough watts is easy but finding a PSU under $60 w/good caps and enough watts on the correct rails isn't so easy.
-
I was looking at the PSU you are working with and if I can shift about 65w from the 12v into the 5v and 3.3v it might just do what I need. The 3.3v is already okay for my app so my brain is on beefing 5v and that's how the suggestion that came out.

...

Azurael, check on eBay and do a google search.
I saw several other dealers selling these at about the same price as in the earlier post.
Those other dealers might ship overseas.

.

[PCBONEZ]

Re: If you're looking for a solid 550W PSU, check this out.

Another oddity:
The data plate on that says 12v at 17+16+8amps. -> [41 amps]
But it says the total 12v is limited to 370 watts. [~30.8 amps]

[gg1978]

Re: If you're looking for a solid 550W PSU, check this out.

I"ve run into issues like that before.. Some boards don't pull enough current on the +3.3V to keep the PSU happy.. A lot of overclocking type slot 1 boards didn't use 3.3V hardly at all.. Some PSU's can tolerate a light load on 3.3V, some can't.. Like i said before, the Acbel's have independant voltage sensing on +3.3, +5, and +12.. It appears the sense wires go into the locations correponding with the regular 20 pin ATX standard, so it should work equally well on 20 and 24 pin motherboards..


Another PSU i've had that hates having a light +3.3V load is Delta's older BB series.. I bought a pair of 300BB, and they absolutely refuse to work with Asus P3B-F or P3V4X, due to light 3.3 loading.. They power newer stuff well though..

[gdement]

Re: If you're looking for a solid 550W PSU, check this out.

I"ve run into issues like that before.. Some boards don't pull enough current on the +3.3V to keep the PSU happy.. A lot of overclocking type slot 1 boards didn't use 3.3V hardly at all.. Some PSU's can tolerate a light load on 3.3V, some can't.. Like i said before, the Acbel's have independant voltage sensing on +3.3, +5, and +12.. It appears the sense wires go into the locations correponding with the regular 20 pin ATX standard, so it should work equally well on 20 and 24 pin motherboards..


Another PSU i've had that hates having a light +3.3V load is Delta's older BB series.. I bought a pair of 300BB, and they absolutely refuse to work with Asus P3B-F or P3V4X, due to light 3.3 loading.. They power newer stuff well though..

It doesn't really seem like a light loading problem though. When the HiPro gradually lost voltage on 3.3, I ended up getting a spontaneous reset under load when it got down below 3.1V. So the system apparently really was using that rail. The other rails were still fine, so 3.3 must have been the cause of the reset.

Anyway, I've switched back to the FSP Sparkle 300W, and it still seems to be happy. All the rails are slightly on the high side, so not showing any potential weakness except 12V which has consistently been in the 11.90-11.98 range. As long as it stays there then it's okay. Nothing has dropped yet, so I guess I'll stick with that PSU unless/until it starts showing a problem. I'll be adding another card and hard drive to the machine, but that probably won't affect it much. I'll keep an eye on the 3.3 to make sure it doesn't start to slide.

Next time I order anything from digikey, I'll look into getting some regulators to modify the AcBel. I suppose they need to be heatsinked, I haven't opened the PSU yet so I don't know how easy it will be to find a spot for it. Looks crowded in there.

[acstech]

Re: If you're looking for a solid 550W PSU, check this out.

What do you guys think about adding a 6 pin PCI-E connector to one of these 550w AcBel's? I've got an old dead Antec with a good connector. I was thinking of using the other side of the 8 pin P4 power connector (as most boards only use the 4 pins) and soldering the appropriate wires together.

[PCBONEZ]

Re: If you're looking for a solid 550W PSU, check this out.

I don't see a problem as long as you have the amps and run one wire per plug pin all the way from the PSU PCB. (As in no "Y" splices.)
Despite labels most PSU's only have one 12v rail by the time you are to output because the so called rails are jumpered on the PCB where the wires connect.
But splicing one wire to feed two pins may exceed current rating of wire where it's only one wire. [Might not affect you on THIS board but if you move the PSU later will you or whoever remember or know to check?]

.

[acstech]

Re: If you're looking for a solid 550W PSU, check this out.

Ok this thing was made to add a 6-pin PCI-E connector. It's got 3 blank +12v holes on the planes right by the wires, just waiting to be filled. The +12v rails are clearly marked and silkscreened out as to where they go, as is ground. Very simple.

What wasn't as simple was taking the thing apart! First you remove the fan. There are two connections between the PCB's that need to come apart. You need to take the screws out that hold the top PCB to the standoffs, raise that, then use a wrench to remove the standoffs. Then you can raise the PCB's enough to get to the connections and remove those.

The primary side has 3 420v, 120uF Rubycon KXW capacitors.

I'll get back with pics when I get a chance.

[acstech]

Re: If you're looking for a solid 550W PSU, check this out.

I got the PCI-E connector added. The grounding was kind of a pain though. No pics were taken.

OBTW, does this look familiar?

http://www.bcchardware.com/index.php...1&limitstart=4

I think we've found our AcBel's bigger brother...

[acstech]

Re: If you're looking for a solid 550W PSU, check this out.

I think this one is pretty similar as well:

http://www.hardwaresecrets.com/article/491

[gdement]

Re: If you're looking for a solid 550W PSU, check this out.

After having raised questions about it, I just want to follow up about the AcBel 550W.

I used one in my nephew's gaming computer, built at Christmas time. It's still working fine, voltages are still good. This is a modern Core2 machine with a GeForce 9800GT video card. The PSU doesn't have the 6-pin connection that big video cards require but the card came with an adapter.
He already replaced the motherboard and processor which dropped 3.3v slightly, but it's still 3.28 so perfectly normal. It changed to that value on first boot with the new board, it didn't slide from wear so I think it's fine.

I've since ordered more of this power supply, even though I don't have an immediate use for them. I don't think they're advisable for older machines that use much 3.3v, but they're solid for newer stuff.

Along with my motherboard design (late nForce2), I think the TI4200 card was a major factor in killing my old AcBel, seeing how much it pulls from the 3.3v rail. I noticed a similar load with another identical TI4200, which was NOS. Both were AOpen brand "Aeolus" cards.
My nForce2 desktop now has a Radeon 9800 Pro, but that model still uses the lower voltages. They transitioned to using more +12v with newer cards shortly after that. I forget the link but there was an article somewhere that measured the draw on many different cards, interesting info.

My desktop is still running happily with a 300W Fortron, but when I upgrade to a 12V oriented system in the future I'll use the AcBels.

[weirdlookinguy]

Re: If you're looking for a solid 550W PSU, check this out.

I really need to order one of these as a backup at least, seeing as how my big system build never ended up happening :/

Is this the one? The original link is dead:
http://hypermicro.com/itemdesc.asp?ic=PSAB001

Kinda suspicious how it's $19 now. I hope it's from the same stock and that the quality didn't go down.

[gdement]

Re: If you're looking for a solid 550W PSU, check this out.

I really need to order one of these as a backup at least, seeing as how my big system build never ended up happening :/

Is this the one? The original link is dead:
http://hypermicro.com/itemdesc.asp?ic=PSAB001

Kinda suspicious how it's $19 now. I hope it's from the same stock and that the quality didn't go down.

Yeah, that's the one. Probably still the same stock.
These are unused OEM units being liquidated, not new retail junk intended to sell at this price. I think the reason the price is so low is because they have a ton of them, and want them to move.