dual power supplies? questions!

A single wire running to the green presumably wont achieve that though, is relying on the psu casing being physically connected to the other one sufficient to bring both grounds together?

I don't think I'd want to use both at once without first understanding how power supplies are put together. If it'll start without the pwr ok connected that bothers me, and shorting it to earth sounds like telling the psu that all is well even were it not.

I'm sure it'll work out of the box, but I'd worry about the reliability.
 
JonJ678 said:
If it'll start without the pwr ok connected that bothers me, and shorting it to earth sounds like telling the psu that all is well even were it not.
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As above - PWR_OK is the PSU telling the MOBO it is OK to boot and run. Not the other way around. Shorting it to ground isn't a trick to fool the PSU into running - it pretty much does nothing. The only thing I can see it doing is providing some minimum load which a PSU requires to run - normally not a problem in a PC as a load is permanently connected, but perhaps this trick is something that sometimes helps people if they want to run a PC PSU as a bench power supply that may have no load connected at times?? Shouldn't be needed for the OP's purposes.
 
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It's been many years since I did this but I seem to remember it was something to with a load required on the 5v line for the PSU to run? It may not be required on modern PSU.
 
All you need is the green on wire. That is all.
I have used these as bench supplies for a while now. I hacked one to 12v lighter sockets for powering astronomy gear in a tent (It also powers red/white cathodes for tent lighting). Works fine!
 
Liampope said:
But out of interest what is the rating of your existing PSU? The 460 isn't exactly a power hungry beast.
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buggered if i know. its a dell box, and you know what they are like for labelling things...

that said, ive very rarely had a dell psu blow up on me (and i look after about 10,000 dell desktops). I might just give it a go on the one psu and see what happens.

TG
 
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Liampope said:
The only thing I can see it doing is providing some minimum load which a PSU requires to run - normally not a problem in a PC as a load is permanently connected, but perhaps this trick is something that sometimes helps people if they want to run a PC PSU as a bench power supply that may have no load connected at times?? Shouldn't be needed for the OP's purposes.
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true enough. i will definitely have the psu loaded. if its wierd and needs the 5v rail loaded as well, i can hook it up to something suitable im sure.
 
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i plan to run an unused black wire to a suitable looking spare screw hole somewhere on the case, held in place with a case screw. (i dont have a bay to bolt psu 2 into y'see)

this should ensure both psu's are working from a common earth.

TG
 
Zaim said:
+1 doesn't make sence imo to use 2 psu's when you can buy a better single unit. if your on a tight budget then this would do the job:

http://www.overclockers.co.uk/showproduct.php?prodid=CA-045-OC&groupid=701&catid=123&subcat=1098

if you want to use 2 460's then i'd get a XFX 650w+
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im just going to use the one gfx card, and if i can do the job with the 2 psu's i have, then i can save the 50 quid plus postage to ireland (all postage everywhere from the uk to ireland is extortionate).

I can't see it causing a problem from an electrical point of view as they will be using a common earth, and none of the wires im messing with will be carrying any load.

obviously im running a small risk using old PSUs, but ive used them both for gaming rigs over thousands of hours of play, so i at least know they are at least fairly reliable. The risk is further reduced because i will be lightening the max load on the main psu by maybe 100W, and the secondary will only be running a 160W gfx card, when it was previously running a 300W+ machine.

not that any of that is really overly important to me. im just doing it because im cheap and it'll amuse me for half an hour or so :D

I may even buy a decent psu when i finally get bored with having 2 going

TG
 
The_TailGunner said:
im just going to use the one gfx card, and if i can do the job with the 2 psu's i have, then i can save the 50 quid plus postage to ireland (all postage everywhere from the uk to ireland is extortionate).

I can't see it causing a problem from an electrical point of view as they will be using a common earth, and none of the wires im messing with will be carrying any load.

obviously im running a small risk using old PSUs, but ive used them both for gaming rigs over thousands of hours of play, so i at least know they are at least fairly reliable. The risk is further reduced because i will be lightening the max load on the main psu by maybe 100W, and the secondary will only be running a 160W gfx card, when it was previously running a 300W+ machine.

not that any of that is really overly important to me. im just doing it because im cheap and it'll amuse me for half an hour or so :D

I may even buy a decent psu when i finally get bored with having 2 going

TG
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Im with you 100%.
As a cheapskate myself I completely understand.

Even at that I would still buy the converter, I started out in eletrical engineering and I see your plan is solid but a £3 adapter is the route I would choose.
 
a Cheap way of joining 2 psu's together and have them work together whilst using your pc's power buton is to make your own dual psu cable.
This can be done by purchasing 2 ATX extender cables and take most of the wires off of one, leaving the green wire and the black wire next to it from the female end.
Then completly remove the male end from this cable, then all you require to do is solder the green and black wires to the green and black wires on the other ATX extender cable.
This way you are not destroying your current psu's and the process is completely reversable.

the cable will look similar to that which mattyfez has posted, except it will have 2 wires connecting them together.

As long as you have a device or 2 drawing power from the second psu you should be fine.

There are also some companies out there that do sell these cables ready made but ive yet to find one in the UK.
You can import them from the USA but the prices are from £20 up and why pay that when you could make one up for about £5 or less
 
sir-les-mp said:
the cable will look similar to that which mattyfez has posted, except it will have 2 wires connecting them together.
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Thought I should mention, that adaptor has two cables, a black earth and the green one is a power on, the black earth is hard to see in the pic, but its there...the green power cable is to tell the secondary psu to turn on, so both psu's power up at the same time when you press the main power button in the pc case.

It came as an accessory with my lian Li case, as it has two bays for power supplies.
 
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redshadows said:
Im with you 100%.
As a cheapskate myself I completely understand.

Even at that I would still buy the converter, I started out in eletrical engineering and I see your plan is solid but a £3 adapter is the route I would choose.
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oh, im totally down with looking for/making a proper converter if i can.

my reply was aimed at the folks saying i should buy a new psu (which, to be fair, i probably should. but i wont!)
 
mattyfez said:
Thought I should mention, that adaptor has two cables, a black earth and the green one is a power on, the black earth is hard to see in the pic, but its there...the green power cable is to tell the secondary psu to turn on, so both psu's power up at the same time when you press the main power button in the pc case.

It came as an accessory with my lian Li case, as it has two bays for power supplies.
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sorry didint see the black cable in the photo.
Only wish Lian-Li had bundled one of those with my case when i bought it which is designed to take 2 PSU's as well.
 
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