CPU fan 3 pin to 4 pin MB?

[niceguygaurav]

Hi all I hope someone out there can help. I've just built my friend a PC and installed a Blue Orb (Thermaltake) CPU fan. When I've attempted to connect it to the MB (Gigabyte GA-8I965P-ds3) I discovered that the Orb fan has a 3 pin female out however the MB has a 4 pin male.

I have never come across this before as I always use Intel stock. The fan connector still fits fine leaving pin 4 empty however the fan is not spinning (Core Duo chip which runs at about 25 degrees).

I am a tad worried as I don't want the chip to blow. I have looked on eBay and noticed that I can buy a 3 pin to Molex connecter however believe that if I use this, then the fan will run at top speed (which is not required).

If anyone has any suggestions, I would be very grateful,


Thanks


G.

[BipolarBill]

Although the connector has 4 pins, the "backbone" is offset to one side so that you can connect a 3-pin fan. That's not working?

I would snip the 3 wires in the middle and try various combinations. I would then use some shrink tubing to make it permanent.

[bruceb]

On your motherboard cpu fan header:

Pin #1 is GROUND

Pin #2 is +12VDC

Pin #3 is Sense (tells bios speed of fan)

Pint #4 is Speed Control

-------------------------------------------------------------------------

You will need to look at the documentation
that came with the fan ... it will tell you which
lead is the SENSE Wire .. it will also say which
should go to +12V ... other wire is the Ground

You may need to move the wires around in the
connector to match it up with the motherboard.
The motherboard should be marked with Pin 1

If not, easy to tell with an Ohm Meter and the power
plug removed from the AC ... just ground one end
of the meter to the case and see which lead has
lowest resistance .. that is the Ground lead

You can then deduce the others as +12V is
next to the Ground pin

[niceguygaurav]

Hi all just to let you know that the fan did fit in the 4 pin slot. The reason it was not spining was because I had to change the bios fan settings to "volt",

Thanks for all your help!