I have to get right next to it to hear it, right now its sideways so the psu is not aimed at the wall. It is certainly the fan and now it is quiet lol. Oh well I have to move it and load stuff on it and play with OC stuff, it will be a while before I can run a game on it. Have other projects to get on as well. If anyone does mess with a psu be very careful they will zap you if you touch stuff in there like the heat sinks, and yes after they are unplugged. Someone crafty should be able to replace a fan, unless its some strange item, but don't say you were not warned about the capacitor charge inside.
Good idea to drain it, but I did that it still buzzed me a little. Can give you a jump if not expecting it.
I would probably peel the cover off carefully and inspect, find out what type fan it is and how its mounted, look for anything non standard, is it plugged in or soldered, etc. It could be 120v fan but most all variable speed are not. But it might not be a typical PC fan you never know, and for cost of a new PSU an expensive fan may not be worth buying for an old psu. I bought a hyper 612 cooler and its huge but the fan is slow and quiet. I thought hey I can put a faster fan on it if needed, looked at a vardar and they are $26 each. I only paid 45 for the whole cooler, not really worth it. It might cool fine and I never need it I was just looking.
Should be good long as new fan is same voltage and near same rpm. You can use small wire nuts, if you get them on good they will stay and not short on anything or tape around them if needed. Use the old plug on new fan.