How can I test a computer power supply?

Dennis January 8, 2012

How can I test my power supply even before installing it into my tower case and connecting to the motherboard?

  1. James Bruce
    January 9, 2012 at 2:30 pm

    Unless you have reason to suspect its actually faulty, then plug it in. On most motherboards, there will be an LED to indicate power supply is connected and working. 

    • Dennis
      January 10, 2012 at 6:01 pm

      What a hassle! Original PSU blew up - literally.  Didn't know if MOBO was fried.  Bought 1st new PSU - something rattling around inside! Bought 2nd PSU that didn't work, blew the 5amp fuse in the 13 amp wall plug.  Bought 3rd brand new PSU and decided to test it before installing into MOBO in case original PSU fried MOBO and caused it to somehow blow fuse in PSU no 2. PSU tested ok and system up and running!  Thanks. 

  2. Anonymous
    January 9, 2012 at 12:36 pm

    if it is important for you and you don't have experience then perhaps to ask a technician to be on the safe side.

    • Dennis
      January 10, 2012 at 6:05 pm

      Thanks for the warning -took precautions and went ahead and metered it.  Test: AOK.  Thanks.

      • Anonymous
        January 10, 2012 at 8:20 pm

        you took the right decision, Prevention is better than cure, glad that the system is running fine for you.

  3. Mike
    January 8, 2012 at 10:08 pm

    You could also simply connect it to your hardware without installing it in the case. Just open the side panel of your computer, connect everything to your hardware and see if it runs.

    Unless you have a system with some "high-tech" airflow design and only passive coolers for the components (CPU, GPU, ...) there is no real harm done running it that way. 

    Some components may have a few degrees more than usual but if that's already causing a problem you should rethink the cooling of the system anyway - components are not designed to run at their limit for an extended time.

    January 8, 2012 at 8:41 pm

    Hello, there are two ways of doing this.  The first way by using a multimeter.  The second way is by using a power supply tester.  The most automatic/easier way would be by testing with power supply tester.  Using a multimeter is not hard, you just have to check connections one by one:

    Testing with multimeter:

    Testing with a Power supply tester:

    • James Bruce
      January 9, 2012 at 2:29 pm

      I thought a multimeter isnt possible because its a softw switch to turn on the power supply? ie, you'd need to actually plug it in...

      • Mike
        January 9, 2012 at 4:29 pm

        To get the power supply running all you have to do is short-circuit the PW_ON (green) cable with the GND (black) on the 20/24-pin ATX connector.

        even a paperclip will do the trick ~ obviously this should be done before connecting the PSU to the power outlet

      • FIDELIS
        January 9, 2012 at 11:18 pm

        Hello, here is a video showing how to test power supply with multimeter:

    • Dennis
      January 10, 2012 at 5:54 pm

      Did some checking on the ATX  v2.01 pinout assignments then checked with multimeter according to youtube link you posted and to the pcssupport urls.  Worked great! Thanks.

      • FIDELIS
        January 10, 2012 at 9:18 pm

        I am glad it worked out ok

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