HomeDesktopsPower SuppliesSimple Power Supply Test

5.1. Simple Power Supply Test

Checking a power supply for functionality can be done without a motherboard.  This can help narrow down a no power issue between the power supply and motherboard.

To Diagnose the Power Supply

1) Remove power, open side panel of PC.

2) Unplug the large 24 pin connector from the motherboard. 

3) Using a paper clip, bend it into a U shape and connect to green wire and any black wire on the 24 pin connector.  See below

4) Connect 120/240v power from wall.

At this point, the power supply should instantly turn on.  The power supply fan will spin and any device connected to power will also turn on.  This would also indicate the motherboard is not giving the "Power On" signal to the power supply.  In this case it could be a possible motherboard or power button issue.  Contact support for further guidance.

If the power supply does not turn on

There are three possibilities if the power supply won't turn on:

a)  Test Failure.  Double check the paper clip is connecting green to black and verify it is touching the metal contacts in the 24 pin connector.  If not, readjust and retest.

a)  Another device or accessory connected has a power short and preventing power on.  To test, unplug wall power, then unplug all devices from the power supply including hard drives, optical drives, and anything else directly connected to the red/yellow/black/orange power supply cables.  Reconnect wall power and test again.  If the power supply successfully turns on, a defective device was connected to power.  Narrow down and replace shorted device.  Otherwise -

b) Power supply is defective.  Replace with known good power supply.

NOTE:  This is test is limited to the basic functionality of the power supply.  It does not account for load failures, overheat failures, or intermittent failures.



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