Testing ATX Power Supplies

Testing ATX Power Supplies

Problems with your computer and you think it is your power supply? Well here is the correct way for Testing ATX Power Supplies. This is a guide for experienced computer builders only. If you are not one, then please take your desktop to a qualified pc technician.

It cannot be stressed enough that this shouldn’t be done by just anyone, you can do serious harm to your computer and/or all of its hardware, let alone to yourself. So save yourself the damage monetarily or physically and emotionally. Ok lets begin shall we.

Tools Needed for Testing ATX Power Supplies

  • The correct sized screwdriver to remove the computer case
  • Then a voltmeter or else a multi-tester and a digital multi-meter would be ideal
  • One paper clip or even a tiny bit of wire, to act as a jumper

If you have done the necessary troubleshooting beforehand and are pretty sure the problem is your power supply, then here is the procedure for Testing ATX Power Supplies. If you feel unsure with this advice, or uncomfortable with taking apart your computer, please take the PSU to a local pc technician or business that can test it for you. Or ask a friend who has the required ability to do it for you.

Before you start testing

Make sure the computer is unplugged from the wall socket, remove the case, and unplug all the power cords from the system board, drives and anything else that is plugged in. You will see that there are lots of black wires on the primary ATX plug, check them all for continuity with your DMM if you have one. Once you have done all this we are ready to begin the real testing.

The ATX testing process

Plug the power cable into the wall, then test between the purple wire and the ground, it should be about 5VDC, if it doesn’t record anything then most likely is the fuse is blown. And if it is drastically over or under the 5VDC, like 2VDC or 8VDC, Then your PSU is worthless and should be replaced.

Now get your paper clip or jumper wire and jumper the green wire to ground, the black wires only please, then the fan on the power supply should spin up (if it doesn’t don’t worry, the fan might just be clogged). Now test all of the wires, red ones all first ideally. DO NOT TEST THE BROWN,GREEN OR GREY ONES. You may or may not have a white wire, if you do, test it.

What results will you get

If any of the are way out of what they should be ( below ) then replace your PSU or perhaps get it looked at by a qualified computer repair technician, the same goes to if any wire records 0 volts. So below I have bullet pointed what each wire should read. And that’s how you go about Testing ATX Power Supplies.

  • Purple (Standby) +5VDC
  • Red +5VDC
  • Yellow +12VDC
  • Orange +3.3VDC
  • Blue -12VDC
  • White -5VDC