laboitenoire

Alright, first of all, I only have done this with old PSUs which have dead fans. I most recently did it to replace the fan in an old 235W Fortron Source (pre-FSP) power supply that resides in my pentium-base DOS machine. I had already replaced the fan once with one that died a week later (smooth...), but the great thing about this PSU is that it can soldier on without a fan. It gets quite warm on occasion, but it will remain reasonably stable. However, seeing as my cheap-ass cheifmax PSU (never buy this. I have a 100W IBM PSU that weighs more than this 450W) just died recently, I had a spare 80mm fan to use. What luck. Also, if you decide to mod your PSU to have one of those 100+ CFM fans, you can follow the same procedure. So, let's get crackin'!

Disclaimer: Working around a PSU can be dangerous, even when it is turned off. The capacitors can hold a charge for a very long time (sometimes indefinitely). If you touch a capacitor by accident, you might get a nasty shock, a trip to the ER, or potentially a trip to the grave. Therefore, please let the PSU sit for as long as possible before opening it up. Some of the charge might dissipate. Also, make sure that you work on a surface that offers a very small chance of grounding. For me, this is a tile floor. Also, try to use tools with heavy insulated grips. You'll at least be a bit safer this way. So please be careful.

What you will need:

1. PSU
2. fan of the proper size
3. electrical tape
4. pliers that can cut/strip wires
5. screwdriver(s)

What to do:

1. Unplug your PC. Remove the PSU completely, as we need a good open space on which to do this. For me, this is the tile floor of my back room.
2. Remove the screws which hold your PSU lid on. There are usually four of them, and they might be covered with some sort of tape that says "WARRANTY VOID IF REMOVED". Gently ease the lid off. If the little black plastic nut is causing the lid to not budge, you might need to get medieval on it. Luckily, this did not happen to me.
3. Locate the fan in your PSU. This shouldn't be too difficult. Check to see: A. What the fan size is. and B. Whether it uses a two or three-pin fan tail. Match your new fan to this.
4. Cut the wires on the fan close to the fan itself. In many cases, this may render the fan in such a way that you cannot reuse it! However, we need as much length as we can get on those wires.
5. Unscrew the fan from its mounts. Save these screws, as we need to mount the new fan.
6. Install the new fan using the old screws and mounts.
7. Now get out your pliers and cut the fan tail off of the new fan as close to the connector as you can. Also, strip off about 1/4 to 1/2" of insulation on each wire that is now severed, including the ones in the PSU.
8. Twist each wire clockwise individually, as this will make splicing a whole lot easier. Now take the wires that are the same color and twist those clockwise, then fold the wires so that the connection is inline with the rest of the wire. Take your tape and wrap a bit of tape about an inch in each direction of the connection. If you want, you could substitute this with heatshrink tubing, but this is what I did. Test the connection to make sure it's strong enough. Repeat this for all of your wires.
9. Place the wire in a place where it will not restrict airflow and then reinstall the PSU lid.
10. Follow Spookedjunglist's FAQ on how to boot a PSU without hookup and make sure that the fan spins up. If it does not, then make sure that you unplug the PSU immediately. Then recheck your wiring. Now is also a good time to make sure your voltages are still good.
11. Reinstall your PSU, and boot up the system. If all goes well, it should boot up and the fan should spin.

Enjoy and Good Luck!

Hollowman8904

I did this to a very loud PSU a few weeks ago. I just opened it up unplugged the 3-pin fan, and screwed in a new one.

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laboitenoire

Yes, well some cheap or old units have the fan soldered in there.

SpookedJunglist

Good job. Would be better with some simple pictures. In the future I will prolly end up doing this so I will take pictures and give them to you to add to your FAQ

Also I edited it to show a link to my FAQ on how to start up a PSU by its self. Anklebiters was created after my original and we dont need duplicate FAQs. Mine was formated better also.

Good job
Spooked

laboitenoire

Thanks Spooky. I didn't have my camera on me at the time, and it is also very cramped in the PSU I did this to.

SpookedJunglist

I got some old junkers laying around. If i forget just PM me so that I can remember :)

noxious89123

is that wise? it would be loud because its a high CFM fan to keep it cool. if you install a quieter fan, it might get too hot.

BE VERY CAREFUL WHEN OPENING A PSU. DO NOT TOUCH THE INTERNALS AS THEY CAN/DO HOLD CHARGE.

Chim3ra

There are some fans that can push a higher CFM while remaining quiet.

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laboitenoire

Updated the FAQ with a disclaimer.