Power Supply Troubleshooting

A power supply can have three stages of existence: Working, not working, or somewhere in between. The “somewhere in between” stage is difficult to diagnose, as the symptoms of this stage can mimic other problems in the computer. A few basic steps can help you determine if the power supply in your computer is bad, or if there is another issue that is causing your PC not to start or run properly.

Quick Visual Inspection

If everything checks out, you can go into the case—if you're comfortable doing so—and confirm that the 20-pin connector from the power supply is securely attached to the motherboard. It's rare, but not impossible for this connection to come loose. It's more likely the power switch from the front panel has become disconnected, instead. This thin wire is will be labeled something like power sw or pwr sw. This needs to be connected to the proper pins on the motherboard.

Testing The Power Supply

We recommend either swapping in a different power supply or buying a stand-alone power supply tester from your local shop. You can use a voltmeter if you have one, but to test a power supply the power must be on and everything connected. This presents the possibility for electrical shock. If swapping in a new power supply doesn't work, you may have either a grounding issue with the motherboard and the case, or the motherboard itself may have failed. You can try removing internal cards and unplugging any hard drives or optical drives as they will sometimes cause a system not to boot if they are malfunctioning.

1. PC Will Not Boot
2. Device Manager Error Codes
3. Power Supply Troubleshooting
4. Computer Troubleshooting Tips
5. Computer Troubleshooting Tips
6. DVD Drive Troubleshooting
7. Hard Drive Troubleshooting
8. Benchtest Your PC
9. Lost Clusters On Hard Drive
10. Bypassing The Case Switch
11. No Fixed Disk Present
12. Top Ways to Break Your PC
13. Diagnose Computer Problems
14. CPU Beep Code
15. Invalid Boot.ini or Hal.dll error
16. My Computer Automatically Reboots