# Jumper to turn on power supply w/o motherboard?



## biohazard41 (Sep 9, 2008)

Well guys im new here ... And i have a question...... I have a power supply that i want to turn on as well without the motherboard... It's an old LiteOn 200W power supply.... I've been reading many forums and all of them say to connect the green and black ones... but mine does not have a green one... Well it does but its a ground that is connected on the power button.... I'm able to leave it on with only three wires connected to the motherboard.. A yellow one, a black one and a red one.... Anyone have any idea what I can do ??


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## dai (Jul 2, 2004)

is it a atx or an at power supply
a at psu has 2 plugs that connect to the m/b
a atx has 1


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## biohazard41 (Sep 9, 2008)

It has two plugs that go into the motherboard... one says P1 and the other says P2............


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## dai (Jul 2, 2004)

it's an AT power supply
look at table 26-6
http://www.freeopenbook.com/pc-hardware-nutshell-2/pchardnut2-CHP-26-SECT-3.html


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## biohazard41 (Sep 9, 2008)

Ok so I looked at it right i want to connect the orage(white) to a ground?? Sorry but the table doesn't make that much sense to me thanks for the help though


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## dai (Jul 2, 2004)

looks that way to me 
i know very little about AT supplies


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## biohazard41 (Sep 9, 2008)

well thanks for all the help dai


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## biohazard41 (Sep 9, 2008)

But I still have doubt... Because I'm able to leave the power supply on while only a red, black and yellow wire... one wire puts out 17Vs and the other one puts out 12Vs......... this is what made me very confused since the power supply only has 5V and 12V outputs so im guessing the 5 and the 12 meet up somewhere....If i disconnect any of those three from the motherboard the power supply goes off.....


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## dai (Jul 2, 2004)

i have asked someone else that may know more on it


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## linderman (May 20, 2005)

I am sorry to say; but I have not messed around with an AT power supply in more than 6 or 7 years 

I might be able to shed alittle more light if you explain what you are trying to do


BTW I dont think the 5 volt should not be combining with the 12volt ?


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## biohazard41 (Sep 9, 2008)

Yes it's a very old power supply........ Im just trying to turn it on without the mother board to connect other components for my pc.....Well I dont know what is happening with the three cables that need to be connected to the motherboard to stay on.....And i found out why it was reading 17V Its because the yellow is ground and the black is the positive and when i tested the black(12v) with the red(5v) thinking the black was ground so now when i test the red and the ground it only reads 5v so yeah they don't meet up.... I can't understand how this AT works if it was ATX it would of worked very simply but I'm kinda giving up on it because it's only 200W and it cant maintain power to the amp i need to hook it up not even at 1/4 of the level of the amp it stays on with just a peak of bass it goes off ......... So now it's all curiosity cause i might just get an ATX


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## biohazard41 (Sep 9, 2008)

Thanks alot guys I really liked these tech forums i will try to stay connected and help other peeps in something that i might know cause i do know a thing or two.


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## Wrench97 (May 10, 2008)

The old ATX PSU's did not have a p_on from the Motherboard they a 110v off/on switch that connected to the front of the case, I actually still have one of these hooked to a HO train platform it should provide 12v and 5v if you have 17v I would have to say the supply is either bad or a special purpose nonpc unit.


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## linderman (May 20, 2005)

yes the AT spec did not have to have a closed loop to fire up ....... but you will find the 12volt rails VERY lacking on the AT PSU they were all about the 5 volt and the 3.3. volt


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## biohazard41 (Sep 9, 2008)

wrench97 said:


> The old ATX PSU's did not have a p_on from the Motherboard they a 110v off/on switch that connected to the front of the case, I actually still have one of these hooked to a HO train platform it should provide 12v and 5v if you have 17v I would have to say the supply is either bad or a special purpose nonpc unit.


 Well like i said I was testing the volts in a wrong way........... it only has 12V and 5V outputs


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## biohazard41 (Sep 9, 2008)

linderman said:


> yes the AT spec did not have to have a closed loop to fire up ....... but you will find the 12volt rails VERY lacking on the AT PSU they were all about the 5 volt and the 3.3. volt


So that means i cant turn in on without motherboard??


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## Wrench97 (May 10, 2008)

No that means they have a switch to turn them on thaey don't need a motherboard connection.


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## biohazard41 (Sep 9, 2008)

wrench97 said:


> No that means they have a switch to turn them on thaey don't need a motherboard connection.


Well Yeah I know but if its not connected to the motherboard the switch doesn't turn it on IT has to be connected I tried it already


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## Wrench97 (May 10, 2008)

Any model numbers on this?


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## biohazard41 (Sep 9, 2008)

wrench97 said:


> Any model numbers on this?


Its a LiteOn
Model #: PA-4022-6F
200W


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## dai (Jul 2, 2004)

most atx psu's have to have a drive or something connected before you cna jumpstart them to test
the at may be the same


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## biohazard41 (Sep 9, 2008)

Well there is nothing connected to the mother board its just the plain motherboard no drives no thing


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## Wrench97 (May 10, 2008)

How did you get the voltage readings from the PSU?
I have a old AT supply running lights and switches on a train platform it turns on by a 115v push button switch connected internally to the PSU.


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## biohazard41 (Sep 9, 2008)

wrench97 said:


> How did you get the voltage readings from the PSU?
> I have a old AT supply running lights and switches on a train platform it turns on by a 115v push button switch connected internally to the PSU.


Yes the switch on the front has full power from the wall its at 120 AC.... I tested all outputs with a Digital Tester.......And yes I'm sure on the readings....... The first thing I did was disconnect it from everything and just try to turn it on by the switch but didn't work so i found the cables that it needs to be connected to the motherboard to stay on.... and try to figure out what did the motherboard did to those cables and i couldn't came up with anything......... So I figure that it might just need to be hooked up to something to turn on and i hooked up a drive to the 5V one and try to turn it on with the switch and still nothing .......... and the only way im still getting it to stay on is with those three cables connected to the motherboard.........


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## Wrench97 (May 10, 2008)

Try using the 12v that's the leads I'm using for lights.


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