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24 pin and 20 pin

I need to test to see if my PSU is working. It's a 24 pin one. I was gonna put one of my spare psu's in my pc but they are all 20 pin and I don't have a converter. So my next thought was to try my psu in another pc, but all the pc's I have are 20 pin. Can I just plug the 24 pin into the 20 pin slot and let the extra 4 go over the edge. (I don't have a 20+4pin but I am assuming it will still fit) Will that work?
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  1. The answer to your question is no.

    There is an easier way to check your power supply. It's called the paper clip test. Disconnect all power supplies cables. Make sure the psu is turned off. Plug the PSU into the wall socket (mains). Insert one end of a paper clip into the green wire pin on the 24 pin power cable connector and the other end of the paper clip into one of the black wire pins near the green wire. That's how the case power switch works. It applies a ground to the green wire. Turn on the power supply. The fan should start. If it doesn't, the PSU is dead.
  2. Best answer
    If the 20 pin PSU is of similar capacity, particularly the 12 volt rail, it will work without the other 4 pins. The other 4 pins just give the PSU a little extra current capacity. With the CPU and video cards having their own 12 volt power source, that extra capacity is no longer as important as it used to be.
  3. trogdor796 said:
    I need to test to see if my PSU is working. It's a 24 pin one. I was gonna put one of my spare psu's in my pc but they are all 20 pin and I don't have a converter. So my next thought was to try my psu in another pc, but all the pc's I have are 20 pin. Can I just plug the 24 pin into the 20 pin slot and let the extra 4 go over the edge. (I don't have a 20+4pin but I am assuming it will still fit) Will that work?

    Yes
    http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24
    Scroll down to second photo
  4. Well, I know that the psu I'm trying to test isn't completly dead because it turns on my pc partly (the lights come on and the fans spin, but I get no monitor signal and I know that the gpu is working fine so I am guessing it's the psu). So I can plug the 20 pin cable into the 24 pin slot on my mobo and just plug the 12v rail and gpu power cables in? It should work like that?
  5. Delluser1 and jsc - As a precautionary measure why not test the power supply by itself before plugging in the power cable to the motherboard?
  6. Sure. The only problem is that neither the paperclip trick nor a PSU tester puts any real load on the PSU.
  7. ^ Exactly
  8. Yes you can plug a 24 pin in a 20 pin motherboard its ok the remaining 4 pins are for pcie 16x cards so yeah you can and you can also put a 20 pin in a 24 pin board only if your using onboard video then its ok.
  9. K I will test it out and let you guys know what happens. My psu is a 500W antec one. If it ends up needing to be replaced, should I send it back or buy a crosair?
  10. If it's still under warranty send it back
  11. Wait, so I can only put the 20 pin into the 24 pin slot if I'm using on board video? Couldn't I just put it in and plug the 12v rail and the pci-e card in with the other cables?
  12. sorry.if you put a 20 pin psu in a 24 pin mobo you cant use a pcie gfx card because the four pins mussing are extra power for a gfx card

    if you want to use a pcie 16x gfx card you will have to use a 24 pin model.
  13. trogdor796 said:
    Wait, so I can only put the 20 pin into the 24 pin slot if I'm using on board video? Couldn't I just put it in and plug the 12v rail and the pci-e card in with the other cables?

    Yes, if the PSU has PCI-e power plugs. But most 20 pin PSU's are old enough that they do not have the 6 pin power plugs. And you cannot use a 4 or 8 pin CPU plug. They are wired wrong.
  14. Best answer selected by trogdor796.
  15. This topic has been closed by Mousemonkey
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