Weird dual PS behavior.

[acrh2]

I'm having some weird dual PS behavior in a new system I am building.
I've pretty much combed the entire internet for dual PS setup info and I still couldn't find the answer. Multiple guides state that shorting green wire pin (pin 14, PSON) and any black pin (GND) would start an ATX PS. Or that it wouldn't, depending on a particular PS.

In my case, it doesn't do either. The PS in question is Antec Truepower 430, and at the moment, I only have 2 Coolermaster Aerogate III fan controllers and 6x120mm fans connected (to be added are 4 harddrives and 2 cd/dvd drives, and a watercooling setup in the future). When shorting those two wires, the fans turn on for an instant, and stop. However, if I quickly short twice in succession, the PS starts and stays on.
Has anyone experienced anything like this before?
Will using a dual PS cable from a CM Stacker work to start this PS?
In a related issue, I am also considering a custom mod where the two PS units would have connected together green wires, and separately, black wires. Does anyone know from where such a modded cable/setup can be purchased?

[Qkjhfhaiguihfma]

In a related issue, I am also considering a custom mod where the two PS units would have connected together green wires, and separately, black wires. Does anyone know from where such a modded cable/setup can be purchased?

Didn't macci (or sampsa, someone) have a box that accepted two or three atx plugs and then outputted it in one lead? Surely something like this could be adapted to your needs

[jinu117]

To be honest arch2... I would be hasitant to do that as current feedback between 2 PSU could be bad. Why not just grab one big PSU? I played with few things today and found out maximum power taken from AC outlet to PSU was only 370 watt.... (that is X2 running 3ghz, 7800gtx, 1 WD Raptor, 1 Seagate 200gb hdd, 4x512mb Mushkin blue, about 3x 120mm fan 2x60mm fans, 1x 80mm fan, 2x 40mm fans, 2x70mm fans, about 5-6 USB devices, DVD recordrr) That is with running prime95 on one and 3dmark on the other one (it is 2 core :P)
Dual prime will yield 340W or so...
Quite obviously, even this 370W is what goes into PSU. What comes out psu is 300W or so (which is what it is rated at even at very generous 80% efficiency... which typically is 70-75%).
Only time I would think separate PSU is really needed would be powering tec...

[acrh2]

My primary PSU is PCP&C TurboCool 510 Deluxe. However, I'll be running 7800gtx SLI, 6 IDE devices, and a watercooling setup. The rest of the box is similar to yours, except I would be using a single core cpu, 7x120mm case fans and 2 fan controllers.
By the way, I figured it out after reading ATX specs from formfactor.com
For psu to stay on, according to the specs, it must be receiving a ttl low signal on PSON pin. I should be good to go when I connect green wires/ground betwen two psus in parallel, like CM Stacker cable does.
What's this current feedback you are talking about?

[jinu117]

http://www.procooling.com/articles/html/on_da_edge_of_psu_technology_-.php

My guess is 510 deluxe should more than handle your entire system well enough. (keep in my system drawing 300W + 4hdd and pump and sli still doesn't net another 200 W no matter how I see it)... my power draw on CPU alone is about 50W north of what you will do with venice... I wouldn't worry about 2nd PSU really :)

[brandinb]

yeah if its pretty cool in your room that pcpc psu can give more then 500 watts also
________
Herbal vaporizers (http://herbalvaporizers.info)

[acrh2]

Thanks for the advice, but I have 2 PSs. I have a case that can take 2 PSs (U2-UFO). I'm going to be overclocking my box. I can't see a good reason to run just one.

[jinu117]

Thanks for the advice, but I have 2 PSs. I have a case that can take 2 PSs (U2-UFO). I'm going to be overclocking my box. I can't see a good reason to run just one.

Another one why you shouldn't... without some major work...

http://www.procooling.com/articles/html/sharing_the_load_between_psu_s.php

If not convinced, go ahead. no one is stopping you. I don't know how far you plan to overclock... (my guess is certainly not enough to kneel your PC&P PSU with component you mentioned). Just know that you ARE jeopardaizing circuits with uneven voltage and current feed as PSU trying to charge each other. Maybe you will be lucky and get away... maybe not. Never know till you try :) Good luck.

PS) LMAO you are the one who name called me at Hardforum. Well don't mind my comments and advices. Good luck.

[STEvil]

The problem may be that you have no load on the +5v rail (assuming the aerogate and fans do not draw from it). Once you add the HDD's and CDROMS the psu should work correctly. Using a spare cdrom+/-HDD might be a way to test until you have them hooked up.

Ricky & Pedro are who had the PSU combiner I believe.

Personally i'd rather not use what was shown at procooling for powering the main system and/or video card (multiple rails is bad enough) but if you've got everything under control there isnt much to worry about.

[IvanAndreevich]

"Your PSU is more than enough for the stuff" -> "But I have two spots for 2 PSUs!"

Adding another PSU will likely do nothing for the overclock :)

[jinu117]

"Your PSU is more than enough for the stuff" -> "But I have two spots for 2 PSUs!"

Adding another PSU will likely do nothing for the overclock :)

yeah only thing I might condone doing is use the cheaper PSU to power ALL fans, water pump and something that doesn't touch the other PSU's rail such as bling bling light :P Even that will take care of nice 50-100W you might be using somewhere on all those 92cfm fans and water pump :)

[STEvil]

you guys might take notice that he has not mentioned using the PSU's in tandem to power the complete system, but only using the second one for devices which will see no voltage differentials (fans, hdd's, cdroms, pumps, etc).

I should have mentioned this before, but "current feedback" means that if one PSU is running 12.5v and the second at 11.5v you have 1.0v of voltage differential which will mean power from the PSU with higher voltage will leak into the lower voltage PSU (ie: backwards through the circuit). The PSU with higher voltage will also tend to supply more power.

This can also happen with PSU's that have multiple rails and is a large cause of "brown molex connectors" on video cards among other things (although just trying to put too much power through them does this easily as well, the molex connector isnt meant for much more than about 45w.

[acrh2]

Just a few comments to clarify.


you guys might take notice that he has not mentioned using the PSU's in tandem to power the complete system, but only using the second one for devices which will see no voltage differentials (fans, hdd's, cdroms, pumps, etc).

I should have mentioned this before, but "current feedback" means that if one PSU is running 12.5v and the second at 11.5v you have 1.0v of voltage differential which will mean power from the PSU with higher voltage will leak into the lower voltage PSU (ie: backwards through the circuit). The PSU with higher voltage will also tend to supply more power.

This can also happen with PSU's that have multiple rails and is a large cause of "brown molex connectors" on video cards among other things (although just trying to put too much power through them does this easily as well, the molex connector isnt meant for much more than about 45w.

Thank you, Stevil. You have summarized this very well. I do indeed want to run cpu/ram/mobo/videocards through the PCP&C PS, and fans/fan controllers/drives/wc through the weaker Antec PS.



"Your PSU is more than enough for the stuff" -> "But I have two spots for 2 PSUs!"

Adding another PSU will likely do nothing for the overclock


I've had problems in the past powering a prescott based system with the Antec, which (problems) have been fixed by replacing the Antec with PCP&C PS. My logic behind using two PSs is the following: since I have 2 PSs, why not use the better, more powerful PCP&C PS to drive cpu/ram/mobo/sli, while use the cheaper one for everything else. The everything else (fans/fan controllers/drives, WC) is mostly 12V equipment, and considering that NF4 SLI chipset + SLI setup is pretty heavy on 12V rail, it seems like a good idea to me. If I do have a problem reaching a certain overclock (3GHz on a venice 3800+ is the target at the moment), I could at least be sure it wasn't due to insufficient power.




Misc dual PS info regarding green/grey wires.


I have summarized what I learned from reading ATX specs from formfactors.org at Hardforums.
http://www.hardforum.com/showpost.php?p=1028037601&postcount=3
It basically boils down to information that, for the most part, contradicts what has been written on the web. It would be nice if someone with more technical knowledge could comment on this.
EDIT: direct link to ATX specs
http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf
page 25+ is where you can find the PS_ON/PWR_OK(PSGOOD) info, although I have't examined the rest of the document.

[SynGroW]

Ricky & Pedro are who had the PSU combiner I believe.


Sampsa & Kamu used that device for their SLI setup

http://www.soneraplaza.fi/GetImages/GetImages_GetImage_jpg/0,2600,58957,00.jpg

[Necromonger]

arch2, I don’t know if this will help you or not, the links below have a lot of information on hooking up two PSU, I used the “speedy 3d way without the relay” and it really worked great for me.

For your particular problem you might want to try shorting pins 7&8 and see if that solves your problem, its part of that PWR_OK(PSGOOD) circuit.

I have read that it’s a good idea to have a load on the 3.3v, 5.0v and 12.0v rails when you fire up your secondary PSU, you can use dummy loads, LED’s, fans, etc, etc.

This is for a 20 pin ATX PSU:
Pin 7 = (Black) Negative SENSE COM.
Pin 8 = (Gray) PWR OK or PSGOOD.

Ouote: From “Burning Issues”

“Using a piece of wire, connect pin 14 to one of the 6 grounds, i.e. pins 15, 16 and 17 to name but 3. If your PSU kicks in then you are probably safe to continue. If your PSU doesn't kick in then you may like to try shorting pins7 & 8 as well”.

Hooking up two PSU:

http://www.speedy3d.com/articles/case_mod_p3/index.shtml

http://www.ocforums.com/showthread.php?t=88976&highlight=Hooking+PSU

http://www.burningissues.net/how_to/power/psu.htm

[k00lance]

yeah only thing I might condone doing is use the cheaper PSU to power ALL fans, water pump and something that doesn't touch the other PSU's rail such as bling bling light :P Even that will take care of nice 50-100W you might be using somewhere on all those 92cfm fans and water pump :)

do above, I do same for tempo. benching rig

[smids]

I use the CM Stacker dual PSU cable fine. Then again, I'm setup in a master slave config where my second one powers all HDU's (2xraptor, 1xIDE), CD/DVD drives x2, watercooling fans and all lights whilst my master one powers the system (mobo, CPU, graphics). This leads to much more stable voltages. They don't affect each other either as there is no direct connection between them.