# [SOLVED] new problem for an old board



## andyxeno (May 9, 2008)

Hi there folks, got myself a little niggle hope you can shed some light please.
So i have an old amd motherboard with pwm control for the front intake fan which has 4 pins and i purchased a new Corsair sp120 led fan which is great. The problem being that the female connector on the fan is 3 pin so it will run yes but it's running all the time full whack. Not a desperate problem as the cooler the better, but having controls on my case for the led brightness and the speed of the fan i would like to use them. Now i have seen many adaptors for sale online but not to connect a 3 pin female ( end of the sp120) to the 4 pins on the board so i can have control. Any ideas how i could make one up? or where i could purchase such an adaptor in the uk? cheers.


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## gcavan (Aug 13, 2009)

*Re: new problem for an old board*



> having controls on my case for the led brightness and the speed of the fan i would like to use them


Should be no need for any sort of adapter. Connect the fan direct to the controller.


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## andyxeno (May 9, 2008)

*Re: new problem for an old board*

Hi thanks for the reply, err i have connected it? Like i say it's running full whack but because the 3 pin female connector from the fan doesn't fit 4 pins on the pcb the speed and the led brightness cannot be controlled.


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## MoonDragn (Apr 22, 2015)

*Re: new problem for an old board*

3 pin fans do not have a speed control for the PWM to control. You need to get a separate fan controller for that. As for the LED brightness, that is controlled by the voltage to the fan. That just goes brighter or dimmer with the speed of the fan. 

Like I said, you need to get a separate fan controller if you want that kind of control. Alternatively, you can look around for software that allows you to control the motherboard's fan voltage. Speedfan for example. However this requires your motherboard to support control of the fan voltage with software.

You can get a fan controller for around $15.


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## andyxeno (May 9, 2008)

*Re: new problem for an old board*

Ok thanks for replies guys, i may not have made myself clear. my bad. I have control for the speed and the lighting on my case with a controller already, which is how it has originally worked ( little pcb connected to a few pots) Now i have changed from stock fan to sp120 the problem i have is that the connections do not match. I am quite aware 3 pins do not have the speed control and also aware how the leds run ( not always dependant on fan speed :wink: mine isn't). so pcb has 4 pin connector--- sp120 has 3 pin connector anyone know of an adaptor or has made one? as i have had no luck searching online. cheers guys


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## MoonDragn (Apr 22, 2015)

*Re: new problem for an old board*

Ok, just wanted to establish that first. The question now is why doesn't the 4 pin fan connector accept the 3 pin plug? Almost all 4 pin fan connectors accept the 3 pin fan plug, the extra pin is ignored. If you have a special fan controller that plugged into a special fan with a special 4 pin plug, then its not a standard fan connector. Would have to see a picture of it to point you in the right direction.

Also, you mentioned the led was on the 3 pin LED fan. You might have leds that act in other ways on other fans but the led on that 3 pin fan only works off the power connected to pin 1 and 2. Pin 3 is speed sensor and there is no way the led would be connected to that.


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## bassfisher6522 (Jul 22, 2012)

*Re: new problem for an old board*

Hey andyxeno....unfortunately there is no adaptor that I'm aware of that will allow this. Like MoonDragn stated....to achieve what you want you will need to buy a separate fan controller to control your fans. Your other alternative is to get a new mobo that does have the 4 pin cpu/fan headers.


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## andyxeno (May 9, 2008)

*Re: new problem for an old board*

@moondrgn, appreciate your input dude as always i've found there's a friendly lot here  but you still got the wrong end of the stick lol. The 3 pin sp-120 connector IS connected to the 4 pins on the pcb ALREADY, that's why i said it's running full whack as the 4th pin on the pcb controls fan speed and as that isn't connected i can't alter speed and for some reason i can't alter led brightness either (separate pot mate so pretty sure it's not speed related, never slowed fan in past) it's whether ianyone knows how to cobble together a lead that would work or know af an adaptor or some such thingamajig @Bassfisher6522 that's a bummer i hope your wrong on that. I would have thought there would be one somewhere as i can't be alone in this niggle. i'm gonna keep looking and if i find any way of sorting this i'll post. It's had a few looks this post so i'll keep my hopes up for now before i pronounce it dead lol. 
thanks for your replies


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## MoonDragn (Apr 22, 2015)

*Re: new problem for an old board*

Ok, I think its better if you read this link:

http://www.tomshardware.com/answers/id-1745500/3pin-case-fans-4pin-fan-controller.html


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## andyxeno (May 9, 2008)

*Re: new problem for an old board*

This particular post hasn't gone well from the get go. Thanks for your input consider it dead. feel free admin to delete.


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## Done_Fishin (Oct 10, 2006)

*Re: new problem for an old board*

I assume you mean this whilst my colleagues may have thought you were talking about the 4 pin Molex connector

http://www.youtube.com/watch?v=TF018JPytSg


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## andyxeno (May 9, 2008)

*Re: new problem for an old board*

Your assumption was correct! That sir is exactly right! thank you very much for this. i knew there must be a way somehow and you have found it!  Thank you again.


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## Done_Fishin (Oct 10, 2006)

*Re: new problem for an old board*

Glad to be of help ... If you are happy with this answer then please mark this thread as solved using the Thread tools menu just above your original question


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## Rich-M (May 2, 2007)

*Re: new problem for an old board*

Great job Done_Fishin.


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