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Using a second power supply WITHOUT connecting to mobo

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jokers_greg

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Jan 31, 2005
Location
Mississauga, Ontario
I need to do a test run of my WC loop, without using the power supply in my computer. I have a 400W kicking around, and I thought to myself, why not use that? I don't know how to get it running without connecting it to the motherboard. The stickies have links that are about connecting two power supplies to one motherboard.
 
I need to do a test run of my WC loop, without using the power supply in my computer. I have a 400W kicking around, and I thought to myself, why not use that? I don't know how to get it running without connecting it to the motherboard. The stickies have links that are about connecting two power supplies to one motherboard.

Easy peasy! Jumper together the Green and Black on the 20/4 Pin connection. This can easily be done with a paper clip or any other kind of conductive wire.
 
Well the point is to try and get the power on. PSU's don't just turn on when you plug them in, obviously.

OP (and now I) want to know how to turn on the PSU without hooking it up to a motherboard, correct?
 
Well the point is to try and get the power on. PSU's don't just turn on when you plug them in, obviously.

OP (and now I) want to know how to turn on the PSU without hooking it up to a motherboard, correct?

You jumper the PSU then use the back power switch to on/off the power... Following me?
 
I get that, but you did say while it was on...

If you do it with the power on.... :screwy:

And to turn a computer on/off, the two mobo pins make a contact, but they don't stay contacted or else it does nothing (ie, holding the power button for 10 minutes).

Does that same concept not apply to the PSU?
 
I get that, but you did say while it was on...



And to turn a computer on/off, the two mobo pins make a contact, but they don't stay contacted or else it does nothing (ie, holding the power button for 10 minutes).

Does that same concept not apply to the PSU?

I did not say do it while the power was on.

It's not like that. A computer power switch is a "jumper" to engage the power on and stay on.

I don't see why this is so hard to understand here... Jumper the unit together via Green to Black, and control the unit on and off with the back power switch.
 
Wont that kill him dead?

No it won't. The explanation you want is this: The Green Wire is a signal wire, not a power supply wire. The switch on the case is called a momentary switch, all it does is connect this wire to ground. This tells the PSU to turn ON. So all he is doing is replacing the switch on the case with a paperclip. Shorting the +12V rail would be a bad idea, as it will probably fry a paperclip, but it won't kill you.
 
I did not say do it while the power was on.

It's not like that. A computer power switch is a "jumper" to engage the power on and stay on.

I don't see why this is so hard to understand here... Jumper the unit together via Green to Black, and control the unit on and off with the back power switch.

I don't mean to be offensive, but your explanation isn't that clear previously. Perhaps that's my because I'm young.

Let me rephrase and you tell me if I'm wrong.

When the green and black pins are connected, it will stay on. Therefore, insert the jumper and use the back switch to turn it off/on.

I basically rephrased "You jumper the PSU then use the back power switch to on/off the power... Following me?" but I added the jumper part.
 
heheh.. i love to use the paperclip (even if i have a psu tester handy), and then pretend im getting electricuted infront of an unsuspecting client.
 
why is everyone so confused. From what I've read, (in one wonderingsoul post)+common sense, is that you need to follow these steps:

1)make sure the PSU you're trying to use is unplugged
2)connect the black and green pins on the atx connector with a wire
3)turn on the PSU or plug in the power cord (if you have no switch)

what is everyone asking about? lol
 
AFAIK, and from experience, you won't electrocute yourself by holding a paperclip to the green/black to turn it on. I've done this several times, with several power supplies, with my bare hand and a paperclip, and never been electrocuted. The green wire does not supply power, and the black wire is just a ground. If you're afraid of being electrocuted still, then just hold the paperclip with a clothespin or something. All you need is a momentary contact (while the power supply is plugged in and switched on) to start it. Stick the paperclip back in for 5 seconds or so and it will turn off. Just make very sure to only hit green and black or you're likely to fry something.
 
All you need is a momentary contact (while the power supply is plugged in and switched on) to start it. Stick the paperclip back in for 5 seconds or so and it will turn off.

THATS what I was looking for! So keeping the paper clip in it will be like holding the power button down! OKAY! So it's no different then touching a screw driver to the motherboard connectors! Thanks Petty, that clears it up for me.
 
You have to leave the "short" in to keep the PSU on, it isn't a momentary switch...

If you short green to ground, the PSU will turn on. If you remove that short, it will turn off. This is NOT like the motherboard power switch.
 
You have to leave the "short" in to keep the PSU on, it isn't a momentary switch...

If you short green to ground, the PSU will turn on. If you remove that short, it will turn off. This is NOT like the motherboard power switch.

that's exactly right. and here's a picture of how to jumper the connectors:

http://www.hardocp.com/image.html?image=MTExNDExNDc1M1RkYkFxWmF2ellfMl81X2wuanBn

and believe me, there is no way to electrocute yourself while doing this. The PSU can be plugged in, the back power switch can be on, it doesn't matter. the connectors are sensors and do not carry any electric load.
 
forgive me if this is off topic but how the hell do you 'fry' a paper clip? what happens? does it melt or break in two -or does something far more mysterious happen?
 
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