I hear a sound toward the back of my tower near the PSU which sounds horrible. It's very loud and am sure its a fan. I think its the PSU fan. Is the PSU fan inside of the PSU or outside of it? Do i have to buy a new PSU or can i just buy a fan like this to replace it? http://www.ebay.com/itm/076-1232-Ap...oling-Fan-076-1232-4-Pin-Genuine/401257968567 It says its for a A1186 when mine is a A1289 but i can't find a A1289 PSU fan. What should i do? Thanks in advance!