Q I think I may have a bad power supply unit on my Dell PC. But, so I can be sure, what are the symptoms of a bad power supply?
BRETT SMITH, PLYMOUTH
A Fortunately, there are plenty of warning signs of an impending failure in your PC's power supply, which converts alternating current from a wall outlet into direct current that your PC can use.
But remember, a bad power supply should be replaced, not repaired. Some electronic components inside can store a big enough electrical charge to be dangerous.
Some signs of power supply failure are obvious: cracking and popping noises when you start the PC, a spark or smoke in the power supply itself or the smell of burning electronic components.
Other signs are more subtle: When you turn on your PC, you should be able to hear the cooling fan start to run and the hard disk start to spin. If those things don't happen, the power supply may be going bad.
Other telltale signs that indicate the PC is getting only intermittent power:
The PC doesn't start up properly, or abruptly reboots while in use.