Computer Hissing and turning off after power plugged in

[ratchet37895]

Hello,
I have replaced the Motherboard and Power Supply as well as replaced the Ram with the working ram from my computer. I have also unplugged the fans CD Drive and HDD from the PSU to check.

Everytime I plug the power cable in the fans spin up, the light on the case goes blue and after 2 seconds the PC turns off. Fans turn off and a small hissing noise emits from the computer. As I did say brand new Power Supply and Motherboard.

Any help would be greatly appreciated!

 

[C12Friedman]

Did the hissing sound occur before changing the motherboard and PSU or is this a new phenomena? Have you attempted to isolate the origin of the noise (most common method is to listen through a paper towel tube)?

 

[ratchet37895]

It happened both times and I have unplugged everything one at a time, even the CPU fan so only the Ram, motherboard and CPU were running it always makes the same sound. Its a very quiet hiss so I havnt really bothered with it yet.

 

[C12Friedman]

Try isolating the noise source if possible.
Was the PSU replaced with the same model? I ask since a hissing sound is often associated with leaking electrolytic capacitors, a cheap PSU may be overwhelmed causing capacitors to leak.

 

[ratchet37895]

Yes, it was replaced with a brand new of the same model, a Corsair vs450.

 

[ratchet37895]

It was the case... I put the exact same motherboard, PSU, HDD, DVD Drive and all other components into my older case and it worked straight away.