check whether a SMPS is in working condition

How to check whether a SMPS is in working condition?

SMPS stands for Switched mode Power Supply. It gives power to all the components in your computer system.

If your computer is dead and even not a single lights glow on your Motherboard, the basic need is to check is SMPS. To do so, remove power cable from SMPS and unplug all connections of peripherals (Hard disk, Motherboard, DVD etc). Now you can check SMPS easily by connecting a small wire between green color(PS_ON) and black color wire (COM) as shown in figure. After connecting, plugin power cable and switch on the SMPS. If SMPS fan runs, SMPS is working.

Their are many other problem too, if computer is dead, but please try this step first.


  1. Thanks for the sharing but the problem is my fan is not rotating but it is supplying power to the board. Is it necessary for the fan to work? please help.

    1. Hi Anuj,
      yes, Fan of SMPS should work, because the transformer inside make a lot of heat, which should be thrown away. Please change the power supply to avoid sudden death of your computer. You can even try to use WD-40 Spray in side of power supply fan. If your fan is down because of rust or moisture or dust, this spray will solve the trouble with very low cost.
      Keep visiting and share your issues on

  2. hi sir,
    my power supply problem is it's sometime work but sometime not work.

    1. Hi Sandesh,
      If you are sure that it's a problem of power supply only, my suggestion is to change it. Repairing of power supply will be 50% cheaper but that will not be a permanent solution.

  3. Respected sir ,
    After connecting the power cable my smps fan is not working but green led is glowing in the motherboard and when i am pressing the power button the inside fan flicks and stops. What to do ???

  4. dude plug in ps on and com to where?

  5. Thanks for solving my problem I was really worries but with the procedure you explained my problem is resolved.


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