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4 pin pwm fans

NimbleJack

New member
I have been scowering your website looking for the answer to this question, forgive me if the answeer is simple =)

All of the crystalfontz cfa631/633/635 and scab units appear to only support 3 pin fans. Its a nice feature to see that that is through pwm, but i am curious which cfa product supports 4 pin pwm fans? I cant seem to find any...

Or is there a way within the cc2 software to change the pwm duty cycle signal from 12 volts to 5 volts so that the cfa 631/633/635 units can support 4 pin pwm fans?

From what i have been able to find, the answer is no to 4 pin support, and no to changing the duty cycle signal to 5 volts from 2 volts. Please tell me i am wrong on atleast one if those accounts...
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CF Tech

Administrator
Thanks for your question.

Right now, all of our fan products only support 3-wire fans.

There is no simple way to convert our 3-wire controllers to support a 4-wire fan.

The 4-wire fans would actually be easier to control than the 3-wire fans, since they are designed to be controlled. Alas, when we designed our fan products, there were no 4-wire fans yet.

Since most modern motherboards now have a plethora of fan connector built onto them, it is not likely that we will release a fan solution that supports 4-wire fans.
 

NimbleJack

New member
Okay, then is there any way to change the duty cycle signal from 12 volts to 5 volts from within the cc2 software?

The reason I ask is because there is a way to wire the fans where it would be possible to attach a 4 pin pwm fan to a cfa633 or scab. The idea I had in mind involved taking a 4 pin fan's regular plug and stripping it apart. Separate the 4 pin fans wires, install the 12 volt and gnd into a regular molex and then install the signal (duty cycle) wire and rpm monitoring wire into a regular 3 pin. With the 3 pin plug attached to the scab controller, and the molex attached to a psu normally, the pwm fan could be controlled as intended. So long as the scab controller sent a 5 volt signal...

This would solve two problems, not worrying about blowing up the scab with too many fans, and proper pwm fan function =D
 

CF Tech

Administrator
The direction of the PWM on the CFA-633SCAB is pulling down to ground from 12v. The direction on the PWM for a 4-wire is up to 5v (IIRC). So it would not be easy to make it work.
 

NimbleJack

New member
Damnit...Well, I guess a weird frankenstein mix of crystalfontz/aquaero control is in my computer's future LOL

Thanks for your quick responses, much appreciated =)
 
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