7v fan mod...

The Halk

The Halk

The Halk

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I run 5 12cm fans in my PC.

I replaced weak ones with stronger ones. Currently I'm using Xinruilian RDH1225S, which run at 0.4A. They're reasonably powerful and I'd like to 7v em.

I run them all in one chain from a single PSU Molex connector.

Then I had a thought. Since I run them all in a chain, then why don't I mod one of the fans wires rather than stick in a modded Y splitter.

Just a sanity check here.

I'm going to swap over the red and one of the blacks (the one beside the yellow, which is the one the fans power from) and that'll give +12/-5=7V rather than +12/0=12V or -5/0=5V (the other volt mod for fans).

I'll only need to do it once, since the fans are all connected in serial they'll get the -5V to their 0V and run at 7V too.

Right?
 
I've read it through 3 times & it does read right to me but then that don't mean **** does it :p
Anyways I love a good mod so post pics before you blow it up & after you blow it up please :D
 
I'm thinking I can 7v mod all my fans with one wire being moved.

Got a camera now, let's see if I can take a decent picture with it.
 
If you run them all from a 7v-ed molex, they will all run at 7 volt.

The way i did this (eons ago!) was to get a molex splitter, cut off one of the splits, and 7v the end of it. This way any fans daisy chained off this ran at 7v.

Just dont plug it into anything other than a fan :p
 
Malt_Vinegar said:
If you run them all from a 7v-ed molex, they will all run at 7 volt.

The way i did this (eons ago!) was to get a molex splitter, cut off one of the splits, and 7v the end of it. This way any fans daisy chained off this ran at 7v.

Just dont plug it into anything other than a fan :p
Click to expand...

That's what I was going to do. This way I think will be tidier.
 
Alright, here's the wires labelled.

The fan uses the ground (there's 2 grounds, it only uses 1, and I've labelled that one). And it uses the 12V.

I intend to switch the ground for the 5V.

I'll switch it on the Molex to the left, which is a male. This is where the Molex from the PSU will plug in. The fan has a molex female on it, which will plug into the next fan.

I'm 99% certain this is right now. It's such a simple thing. I'm just being cautious because it's electricity and I don't want to hear a pop and see a little puff of smoke.

fanmod1.jpg
 
afaik, and can remember, thats correct, your fans will only "see" the difference between the 5volt line, and the 12volt line, giving you 7 volts :)

Its an old trick :D Might be worth just checking your PSU lines in the BIOS to make sure it will be stable, and work ok.

I dont know how modern PSUs cope with 7volting! Last time i did it was back in the Sparkle PSU days :)
 
So this is it after I've switched em over.

I've connected a Molex so you can see the input.

fanmod2.jpg


The fan should be getting fed 12V and -5V. The output from the fan should be -

12V - 12V
Ground - -5V
Ground - Ground
5V - Ground

And since the next fan will use the top two connectors it'll be 7volted too. And it'll pass the same power on each wire to the next fan etc.
 
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