5v fan connector

[Eric_K]

So I wanted to make my case fans quieter, and I got a molex adapter cable to put in-between my fan and my PSU. I removed the yellow cable and a black cable from the molex adapter. The PSU and Fan is left unchanged. When I turn on the PC, the fan doesn't start.

Here is an example: http://media.bestofmicro.com/0/G/312352/original/molex-01-EN.png

Is it possible to do this with an adapter or do I need to actually change the cables in the fan connector? If I can do it with the adapter it would be so much more convenient.

Also I plan to connect another fan to the fan connected to the molex adapter, is this safe?

 

[Hlsgsz]

Why bother with all this? most motherboards can controll PWM fans.
Try SpeedFan.

 

[Eric_K]

Why bother with all this? most motherboards can controll PWM fans.
Try SpeedFan.

my fans aren't PWM fans

 

[Hlsgsz]

Many motherboards support adjustiing the fan speed through voltage and, if the MB supports that, SpeedFan will work. Basically, if you can set your fans to "silent" in the bios, you can also control them with speedfan.

 

[Eric_K]

Many motherboards support adjustiing the fan speed through voltage and, if the MB supports that, SpeedFan will work. Basically, if you can set your fans to "silent" in the bios, you can also control them with speedfan.

I've tried that, but the BIOS has no control over the fan speed

 

[Hlsgsz]

Many motherboards support adjustiing the fan speed through voltage and, if the MB supports that, SpeedFan will work. Basically, if you can set your fans to "silent" in the bios, you can also control them with speedfan.

I've tried that, but the BIOS has no control over the fan speed

You've tried speedfan or setting teh operating mode in teh bios?
Anyway, what's your MB?

 

[Eric_K]

MSI A68HI AC
https://www.msi.com/Motherboard/A68HI-AC

Vantec Tornado 80mm Double Ball Bearing High Air Flow Case Fan
http://www.newegg.com/Product/Product.aspx?Item=N82E16811999612

 

[Paperdoc]

I can see the problem. First of all, there's no easy way to plug those fans into a mobo fan header because they only have a connector for 4-pin Molex output from a PSU. To connect to a mobo header you'd have to change the connector system on the end of the fan wires.

Now, what you want can be done, but you need to make another change. If you look closely at the wiring, the fan has two wires from it, Red and Black. The PSU output has four wires - Red, 2 Black, and Yellow. When you push them together, the fan's Red connects to the PSU output's YELLOW wire, and Black to Black. To get 5 VDC to the fan, you have to change the position of the fan connector's Red wire so it will line up with the RED wire of the PSU output. Then make sure that the fan's Black wire lines up with one of the Blacks from the PSU. What you did by removing the Yellow from the PSU is disconnect the fan's only power source so it can't run.

You should realize a small risk in what you're doing. A 12 VDC fan motor will not start up if the voltage supplied to it is too low, and that does not mean right down to zero. Many such fans will start up given a 5 VDC supply, but as they age and the bearings become worn and stiff that may fail. So it is up to you to check frequently that the fans you modify this way actually do start up and run.

For connecting a second fan, yes that is safe. A Molex output from a PSU can supply lots of power to fans. The WAY you can do it is simple. The fan comes with TWO molex connectors at the end of its Red and Black wires. One of these connectors is the male one with 4 pins inside a shroud, and that is the one you plug into the PSU female output. The other is a female Molex that you can use to plug another identical fan into so it gets the power, too. It's just a way to let you connect two or more fans to a single PSU output.

Now, re-examine how you will modify the connectors to get the first fan to run on 5VDC. The RED wire from the fan is joined at the male connector back to the YELLOW wire that passes on to the second (female) connector. You really want to snip that Red from the fan off there and splice it onto the RED wire from the Molex connector so it takes the 5VDC supply to the fan. If you do this on BOTH your fans, then you can plug the second fan into the female connector from the first fan, and both will be modified to work as you want.