Can I plug a 4 pin fan into a 3 pin header? (PWM)

[FormatC]

I found a great deal for 80 MM PWM Fans which my older case uses and my fans are all old and about to die (Plus there full of cat hair) so can I plug these fans into a regular 3-pin MB header or a Molex with the proper adapter? Since these fans put out 59/46 CFM/DBA I want to build a fan bus what would I need to use the PWM circuit already in the fan in my fan bus? Thanks

[kenc51]

Yeah it will work ok, no problem! The pin layout is: Pin 1 = +12V | Pin 2 = GND | Pin 3 = Speed sensor | Pin 4 = PWM pulse
The fans are designed to work with a 3pin header as well.

[stev]

Some PWM fans will not work without PWM feedback in the loop. You'll just have to try it to see if your fan will work that way or not. If it doesn't then don't toss it out, it will still work with the 4-pin PWM control.

[FormatC]

Is there a circuit I can make to simulate a 4 pin MB header? and if the fan does work at all with the full 12 Volts will it run at full speed?

[stev]

Is there a circuit I can make to simulate a 4 pin MB header? and if the fan does work at all with the full 12 Volts will it run at full speed?

http://www.analog.com/library/analogdia ... speed.html

Or the cheap and easy way.
http://www.bit-tech.net/modding/2001/12 ... ntroller/1

If you prefer, get one at a good price at Frozen.CPU or the Zalman made unit to save time and any hassels. (Zalman ZM-MFC2 Multi Fan Controller)

http://www.frozencpu.com/cat/l3/g34/c17 ... Page1.html

A fan controller with PWM isn't an easy thing to find, but not impossible. So shop around.

Vantec Nexus and Sunbeam Rheobus are PWM fan controllers to consider too.