How do you know when a PSU has failed?

[pirateguy]

One day my computer would not turn on. I tried multiple plugs and outlets, but there were no signs of life in any component. No lights, fans, or noises on anything, including the PSU, so I assume the PSU is broken. Actually there is sometimes a noise when I turn the PSU off and back on...it quietly goes *ZOOoot*, like a discharging capacitor or something.

I just want to make sure I'm correct on the PSU being the problem and not something strange like the PSU not turning on because the motherboard it's connected to is broken. I assume the PSU fan would turn on no matter what it's hooked up to, but electronics are not my number 1 skill.

 

[TemjinGold]

Can you borrow a spare psu from a friend to test? If not, I would buy one from a place with a good return policy to try.

 

[CoinOperatedBoy]

With the PSU off, you can use a paperclip to short the green wire on the 20- or 24-pin connector to ground (black). You should have some load on the PSU (a fan, for instance), but not your mobo or any critical component. Then switch the PSU back on and see if its fan spins up. Google for instructions on testing PSU and you can find diagrams and step-by-step instructions.

Ideally you could get ahold of another PSU to test, or even a multimeter to check the voltages yourself.

 

[CoinOperatedBoy]

Double post. Mods feel free to delete.

 

[pcgeek11]

Originally posted by: CoinOperatedBoy
With the PSU off, you can use a paperclip to short the green wire on the 20- or 24-pin connector to ground (black). You should have some load on the PSU (a fan, for instance), but not your mobo or any critical component. Then switch the PSU back on and see if its fan spins up. Google for instructions on testing PSU and you can find diagrams and step-by-step instructions.

Ideally you could get ahold of another PSU to test, or even a multimeter to check the voltages yourself.

Use the paperclip to turn on the PSU with only a fan connected to a Molex connector then read all for proper voltages iaw this link at the bottom of the page:

http://www.helpwithpcs.com/cou...basics-inc-pinouts.htm