How do you test a power supply?

[ricoman]

My computer keeps kicking off. I changed my ups and it continues, so I suspect the power supply. Is there a way to check it or a diagnostic software (free) that can? A couple of the times it went down, the normal on/off switch wouldn't work, I had to turn it on and off from the back to reset it. Any ideas that might cause this if it's not the power supply? Thanks.

[rumplestiltskin]

There are inexpensive power supply testers ($20 or less). Google it.

However, from your description, it does sound as if the PS is in the process of shuffling off its mortal coil.

[classfour]

I hope you find the problem - I had one power supply that fried a CPU. It was new out of the box.

[redwudz]

You can check the PS voltages in BIOS, or with a program like HWMonitor: http://www.cpuid.com/softwares/hwmonitor.html

You can also turn on a PS out of the case by shorting pin 15 on the ATX PS connector to a ground pin. A PS tester may not tell you much except that the PS is outputting the proper voltages. It may not load down the PS correctly to show that it is also capable of outputting sufficient amperage.

The easiest test is a substitute PS. Another easy check is to monitor the amount of heat that the PS outputs. If it's hot like a hair dryer, you may have a problem. As mentioned, a failing PS can take out the whole computer. Not something to try to economize with. I stick with major name brands.

I should also mention that a intermittent short can shut down a PS automatically, usualy with no damage to the PS.