Power Supply Making Loud Noises

I have an "ANTEC EARTH WATTS 500watt 80 Plus" psu that is starting to make loud noises. It's happening when I turn the pc off for a while... Say 5 minutes or more. It'll start humming loudly until I shut it off, and press the power button 5-10 seconds after shutting it off. It always comes back on without the humming sounds and works perfectly the second time around.

Today it was acting even weirder. I had the pc off for a while so as usual it made the sounds when I powered it on, but than next thing you know it went away on it's own after about 2 minutes.

Does anyone know what could be causing this? I tried vacuuming the back fan vent. It doesn't look SO dirty back there. Just normal dust build up... This thing is about a year old. I also looked back there to see if the fan wasn't spinning at anytime, and that's not the case because it seems to spin fine with and without the loud sounds.


Thanks

 

Asked and answered here: http://www.geekstogo.com/forum/Power-Supply-Making-Loud-Noises-t239960.html#entry1543418