I just took an 80mm fan from a dead PSU and I wanted to use it inside my case. Simple question: how do I get the fan to work since it obviously doesn't have a 4 pin molex connector? How can I plug it to my new PSU?
Please, pictures of this How-To would help.

sorry no pics, but for a quick way to do it is if you have extra molex extenders or y splitters around and you wind the leads from the fan around the correct 2 pins on the molex and then just seal it with electrical tape, or solder it.(pins are usually yellow and one of the black ground wires)

There are also adapters for 3 or 4-pin fan headers to a 4-pin MOLEX connectors. use the adapter and then plug it into a PSU 4-pin MOLEX.

Yeah, but some PSU fans(especially older ones) are wired directly to the PSU PCB. You have to cut the wires, then solder them (or twist the wires together) to a 3 or 4 pin connector. I always take out the PSU fans, some work pretty well, and some are ridiculously underpowered.

Yeah, but some PSU fans(especially older ones) are wired directly to the PSU PCB. You have to cut the wires, then solder them (or twist the wires together) to a 3 or 4 pin connector. I always take out the PSU fans, some work pretty well, and some are ridiculously underpowered.

And some are hideously loud. Depending on its age, it may not be worth the effort. Even good fans have a finite lifetime - although if they spin, they at least go on the spares shelf. Kinda like the ol' folks home.

This is just my opinion but you can get 80mm fans for really cheap and I dont see the value of an old PSU 80mm fan. The powersupply failed for a reason... and theres a good chance the exhaust fan failed. Its really not worth the effort to convert it to the standard 3 pin molex. But your question was how to do it and I am just questioning your reason for it! I probably shouldnt be doing that, so break out the wire cutters, soldering iron and spare molex connectors and get to work you sound like a true modder and your working with what you have and thats pretty damn respectable... but you might want to save yourself the work and get yourself a silent fan made to go in your case. Either way goodluck!

That hypothesis is easily verified...

Effort? In the first place, I'd put a mini fan plug on cuz molex is bulky and just so last decade. But effort? We're talking like a minute to see if the fan is alive and a few more to attach a plug. Effort?

To add it to the fan shelf, naturally. It's like a savings account. What if the hot chick from down the street comes by late at night and asks if you have a spare PS fan? You'd be SOL but I'd be able to let her choose her fave LED color. I know which one of us would get to overcock the front side bus that night...

Great stuff. Man, post of the day