To be sure, the power supply is one of the most critical components inside your PC’s case. In fact, when the power supply quits working everything else quits working right along with it. If you suspect that the power supply in your PC might be defective, this article will explain how to replace it with a new one.
First, you need to determine if the power supply is indeed defective. Without a power supply tester or enough knowledge to be able to check one with a voltmeter, there is no way to be absolutely certain that the power supply is really bad – but you can get a pretty good idea. Here’s a quick and dirty test:
1 – Is the power supply’s fan running? If not, verify that the computer is plugged in to a working electrical outlet and turned on. If the PC is getting power but the fan isn’t turning that’s the first clue that the power supply might be defective.