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Splicing a fan into a SATA power cord.

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  • Hewlett Packard
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Last response: in Components
October 6, 2010 5:45:20 PM

I own an HP Slimline s3127c, and am annoyed at how loud the cpu cooler can get at high temps. So, to keep temps in the case at a minimum, I am going to cut a hole in the side and put a 120mm fan there (Similar to what this guy did on - The problem is, there are no extra fan headers on the mobo, and no molex connectors on the PSU. I am new to working with computers, and in the near future plan on building a gaming rig. For now I have to deal with this hunk of junk. I need to splice the fan into a SATA power cord, but don't know how. Advice?

More about : splicing fan sata power cord

October 6, 2010 7:12:05 PM

The only available power cord is SATA? When you say there are no molex, does that mean at all, or just no free molex connectors? If there are Molex in there that are used, get a Molex Y-Adapter/Splitter. If not, buy one of these to convert that SATA power to Molex (much safer than splicing into the cable):
October 7, 2010 3:39:36 AM

Thanks for the suggestions. The power supply that come with the slimline I have only has 3 connections, a micro 24-pin for the mobo and 2 15-pin sata cables. That is it. And they are used by the hard drive and DVD Drive. Your 3rd suggestion would work, but I don't feel like paying 7 more bucks. So I'll try my hand at splicing. If I could just find a good guide or good advise on how to go about doing it, I'll be happy. Thanks anyway.
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a c 105 ) Power supply
October 7, 2010 7:13:08 AM

Heres a pinout guide, might help you decide which wires to, NO!!!! NOT THE RED WIRE, OMG ANY WIRE BUT THAT ONE!! :p
have fun man **Editbut I vote for the splitter as best option as well
a c 144 ) Power supply
October 7, 2010 8:30:01 AM

If the system is still under warranty, modding the PSU cabling will void it. Also, if you screw up, you can cause serious damage. I encourage you to use the splitter, especially if you have little or no experience soldering.

Those neat soldering jobs you sometimes see in modded projects takes a certain amount of knowledge, skill, and tools to pull off.

With or without the splitter, if you are going to splice, you have several options.

For fully speed (noisy), you can splice the fan into the yellow and black wires, putting 12 volts across the fan. Yellow and orange wires give you 9 volts across the fan. Yellow and red yield 7 volts.

Keep in mind that the more you try to do, the greater the risks are.

Best solution

October 7, 2010 1:50:24 PM

It's pretty easy to manufacture your own Molex connectors & cables.

Try to find a store that supplies the pins and connectors e.g.:

Examine up-close one of the pins, and strip wires enough
to "crimp" the exposed wire section.

Then, there should be a second set of clamps
to crimp the insulated part of the wire.

Finally, insert each pin into the correct hole
in the Molex connector.

Proper Molex pins have "fan-out" fins that
compress while being inserted into the connector hole,
then expand to resist removal.

You'll need some extra yellow and black wire,
and you'll need to splice them with the corresponding
wires on one of your SATA power cables.

You don't really need to solder that splice,
but electrical tape is highly recommended;
otherwise, the splice will be exposed
and that is a NO-NO!

p.s. We've refurbished several older PCs,
and we usually discard the older PSUs:
we snip off the Molex connectors and wires
to have a supply of this stuff on hand --
for custom hot-wiring :) 

October 7, 2010 8:22:18 PM

Thank you all for the info. I think I will pull out a molex connector from an old PC I have, and splice it to the 9 volt config (yellow and orange wires). I've had this Slimline for 3 1/2 years, so I'm pretty sure the main hardware replacement warranty is gone. If I blow up the psu, or ruin the DVD Drive by splicing into the SATA connected to it, Oh well. I thought about replacing the PSU with a 260 watt one anyway (so I can put in a Sparkle Low Profile GTS250), and the DVD Drive is dying. All in all, I'm not too worried. As long as I get a little practice out of it.
October 7, 2010 8:27:55 PM

Also, would it be possible to splice into the 4-pin CPU cooler connection? Just for future reference. That would allow for variable fan speed depending on the CPU temps. But I'm sure it would be much quieter that without it.
October 7, 2010 8:40:27 PM

I wouldn't go the 9V or 7V route, I'd just go from 12V to Ground (black) or 5V to ground (black). PSUs are designed to provide power, that is, they're really current sources. By going from 12V to 3.3V, you'd have to have current from the 12V line go BACK over the 3.3V line, which isn't by design (the PSU wants to provide current OUT the 3.3V line, and sink it back over the ground/0V/black lines. Many SATA drives are designed to NOT use the 3.3V line because many people use molex-to-sata apaters, so the 3.3V line might not sink current. You can try it, but it might not be healthy.
October 10, 2010 4:14:09 PM

Last night I went ahead and spliced to the 12v and 5v, the way a molex would normally be configured. Thanks for the advice, everything went well, it looks nice, and there should be no problems
a c 105 ) Power supply
October 10, 2010 7:08:08 PM

cool, pictures please? :p 
October 14, 2010 1:38:36 AM

I'll post pictures. As soon as I can get my camera to work properly. In the mean time, I cut a hole in the side of the case, mounted a Cooler Master 120mm Blue LED fan with a mesh grill, and it doesn't look too bad. My idle temp is 12C (used to be 30-40) and my load temp is around 45-50C (used to be 70-80). Also, my cpu fan used to rev up to high rpm (really annoying sound) around 55 - 60C. It never does it now. I am sufficiently happy with the result. The 120mm fan does make my PC a little louder than it used to be at idle, but its not really noticeable. Of course it is running at 12v. I'll post pictures tomorrow.
October 14, 2010 2:45:23 AM

Molex Connection

Method of Splicing (Just wrapped them around each other as shown, and covered with electricians tape)

The Fan/Final Product

At Night

a c 105 ) Power supply
October 14, 2010 6:08:36 AM

It will be louder partly because the fans outside the case,not sure if you have room inside ofc :) 
And I'd verify that 12'c temp hehe, but otherwise nice mod mate, :) 
October 17, 2010 9:01:11 PM

Best answer selected by roinujnomma.
a b ) Power supply
October 17, 2010 10:26:30 PM

This topic has been closed by Mousemonkey