7v fan mod...

The Halk · 18 Dec 2008 at 11:49

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?

GinG · 18 Dec 2008 at 12:49

Please post pics once done, interested in this.

Thanks

The Halk · 18 Dec 2008 at 12:58

The fan mod?

Edit : What else could it be

I'll snap some just now if I can lay my hands on a camera.

4T5 · 18 Dec 2008 at 13:05

I've read it through 3 times & it does read right to me but then that don't mean **** does it

Anyways I love a good mod so post pics before you blow it up & after you blow it up please

The Halk · 18 Dec 2008 at 13:12

malc30 said:
I've read it through 3 times & it does read right to me but then that don't mean **** does it
Anyways I love a good mod so post pics before you blow it up & after you blow it up please

Surprised you stayed awake

Bradley8988 · 18 Dec 2008 at 13:16

I dont get it. Your doing something different that just 7v modding a fan?

The Halk · 18 Dec 2008 at 13:19

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.

Bradley8988 · 18 Dec 2008 at 13:25

Yea you can its simple. The case i just sold had 2 yates running from one volt mod.

Malt_Vinegar · 18 Dec 2008 at 13:27

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

The Halk · 18 Dec 2008 at 13:30

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

That's what I was going to do. This way I think will be tidier.

The Halk · 18 Dec 2008 at 13:36

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.

Malt_Vinegar · 18 Dec 2008 at 13:42

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

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

The Halk · 18 Dec 2008 at 13:52

So this is it after I've switched em over.

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

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.