I'm using a Gigabyte Odin Pro 800W PSU which I have been generally very happy with - until a few months ago when one of the bearings came loose? and started jumping around in their making a horrible noise. The fan still operated correctly and I put up with it for ages, until that is, I got stuck into these forums
Anyway, I've gone and replaced the fan and it's all working now. My problem was I only did enough reading to put the idea in my mind that it was possible to replace the fan. Needless to say I made a few mistakes along the way and I thought I might share my journey with you so others can learn from me
So my adorable PSU
After I drained the PSU I went to work undoing all the screws to open the case. Easy you say. Well so did I. After all the screws were removed I opened the cover. When I say 'open', I mean I yanked and pulled and pried and prodded and warped the fan side of the casing until I could at least get the fan out. Every bit of logic in my head told me it shouldn't be this hard, I must be missing something. This lead to mistake number 1.
Schoolboy error #1 - If the case isn't coming off easily you have missed a screw!!
I looked many times over the case until I found 1 hiding under a sticker.
After punching myself a few times I continued on.
The Odin fan is not plugged directly into the pcb. Rather, it has a handy plug running from the pcb.
Once the case was open (properly) the fans were ready to be swapped. The Odin Pro series have 140mm fans. "No problem" says me. A quick trip to the local PC store and back and I was in possession of an Enermax T.B. Silence 140mm case fan. Sure, I knew I'd have to mod the wires but that would be no problem.
Now, onto the modding.
The Enermax came with a standard 3pin mobo plug and a molex adapter. I threw the molex adapter aside - wont be needing that anymore.... Now I just cut the wires, confirm the +ve wire is the middle one, join the +ve and -ve to the appropriate fan pins on the Odin and I'll be done.
Problem number 2. Even now I can only work out part of this problem.
Firstly, from looking at other 3pin case fans I have and using, it appears the pins are: 1.Signal 2.+ve 3.-ve I can't see how this could or would change between fans as this must be a standard mobo pinout. Secondly, after reading thread after thread here and elsewhere I learned that case fans only need +ve and -ve wires to function.
So I test the setup by joining the +ve and -ve wires to the corresponding fan wires of the psu. Gave it power (by plugigng it into the mobo and pressing the pc power button). The pc powered but the psu fan had nothing. I was going to go into more detail here but to cut to the short story I found that this fan simply would not spin unless the 3rd (signal) pin was connected to the -ve wire.
Adding to this confusion, I also learned another important lesson. Different fans have different voltage requirements to spin up
I measured the psu fan as 5 volts. It appears this enermax need more than that to get going. If I manually started spinning the blades the psu would keep running it. It just didn't have enough oomph to get it going in the first place.
Manually spinning the fan inside a psu is obviously not acceptable. Apart from putting fingers near big live currents is bad, let alone worrying about the computer waking from sleep etc when the user isnt' around. So, my solution was to power the fan from a steady 12v source. I could have chosen a spare fan plug from the mobo but I didn't want the psu to be changing the fan speed based on the mobo temperature. Instead I decided to go and find the molex adapter, which would give me a steady 12V while the PC is running. Either way I had to repair the case fan lead.
It's a bit blurry but I soldered the wires back together and wrapped it up in heatshrink.
So, I installed the fan back into the psu and routed the power lead out of the psu case alongside the 24pin leads (there was plenty of room for this). Threw the molex adapter on this original connector and plugged it into a spare molex plug.
Voila!! All done and working!
Although the PSU fan is now no longer controlled by the psu, I'm not concerned of overheating as now its spinning at a constant 12V, rather than the original 5V (unless someone comes along and tells me that this logic is flawed!!)
What I don't understand is after looking at the molex adapter that cam supplied with the fan, I see it only passes on the +ve and -ve wires. While this make sense (because, well lets face it - it's molex), it contradicts my earlier findings that this fan must have the signal wire hooked in with the -ve wire. The adapter certainly doesn't seem to jumper the wires in any way.
So, that's it. Hope this helps someone!!