MacPro Fan PinOut

[iDVD]

Hello, I'm doing a MacPro case mod project. And I want to connect MacPro fans to motherboard or power supply, but I'm having problem connecting it. I can't find which pin goes where. Maybe someone knows how to connect it right ?If I try connect first pin(GND) to ground and second pin (VCC) to +12V nothing happens.If I try connect first pin(GND) to ground and second pin (VCC) to +12V nothing happens and fourth pin (VM) to +5V
My guess is:
GND = Ground
VCC = +12 (but I'm not 100% sure)
O / P = Sense /Tacho (but I'm not 100% sure)
VM = PWM (but I'm not 100% sure)

I take some pics and mane diagram for more understanding if i helps.

Maybe someone know how make this thing work ?

​

 

[Yuvinmw]

Hi there. I don't have much experience with these Mac Pro fans but I've worked on the Fans from the iMac G5, iMac Core Duo, iMac 27' 2010, and the PowerMac G5. What I suggest is that you get an ATX PSU with a Molex connector and start jumping wires. The pinout of a Molex Connector is:

RED - 5V
BLACK - GND
BLACK - GND
YELLOW - 12V

Start connecting these wires to your fan. The way most of these fans work is you connect GND to GND from the molex, connect VCC to the 12V output, leave O/P (Tach I presume), and connect the 5V from the molex connector to VM (I presume this as the PWM Voltage). After this is done, power on the PSU and see if it spins. No reason as to why it shouldn't. If this works and you are planning on using the fans, I'd recommend a fan controller or an in-line resistor. Good luck, and I hoped this helped you.

Yuvin

 

[iDVD]

Didn't work for me your metod:
GND -> GND
VCC -> +12v
O/P
VM -> =5v


Somehow this man (Powerpcg5) found way to make it work, he using external components
in this post. I wrote a post in his topic but no answer yet. I can't write PM to him becouse of forum rules (I need have 75 posts to write other person PM, nonsense)

 

[QuantumDog]

My apologies for posting to an old thread, but since you haven't received a reply, I'll provide a description for the benefit of others who may read this.
The fan in the MacPro case isn't really compatible with an Intel based motherboard. That being said, you can get it run with just a few simple tricks. It's been a few years since I built my box using a 2009 MacPro case, but if memory serves, here's what you do:

The pinout for the MacPro fan looks like the following:

|______|
| 1 2 3 4 |

Pin 1 - ground
Pin 2 - Vcc, or 12V
Pin 3 - Tachometer sense pin
Pin 4 - Speed control pin (1V = slow, 5V=moderate, 12V=jet engine fast)

The problem is that on your motherboard, pin 4 uses the Intel fan control standard. To vary the fan speed, the voltage is toggled on and off, with the duty cycle representing the fan speed. So if the control is on for a 1/4 of a second, and is then off for 3/4, the fan would run at 1/4 of full speed. The Mac Case fan wants an actual voltage which would be on continuously at ~3v for the same quarter of full speed.

The simple trick is to use a small knife and squeeze the retaining pin on the Pin 4 plug connector. The Pin 4 wire will pull out of the socket. If it doesn't slide out easily, you aren't squeezing the retaining tab in the right spot. One pin 4 is out, you can safely plug the socket into an Intel motherboard fan connector port. Everything is ready to go, you just need to apply a voltage (0 to 12V) to the speed control wire that you just release from the connector. A good source is to tap straight from the Power Supply Unit (PSU) using one of the +5V pins from an unused disk drive molex connector. If all is well, your fan will be spinning at a good rate, and you can go into your BIOS display to see the actual fan speed.

My ASUS rig has a few of these fans running using 5V for the fan speed setting. There is plenty of cooling for a 2700K CPU, and I haven't really found the need to increase the fan speed. Someday, if I want to overclock the system, I could implement the variable speed feature. This would require building a small circuit to convert the motherboard pin-4 speed signal (pulsed on/off) and generate a continuous 0 to 12V signal that would feed into the MacPro fan. The general approach is to use the motherboard speed signal to drive a transistor, which acts as a valve to vary a 12V power source. The output would be a pulsed 12V signal. You'd connect the oscillating 12V wave to an appropriately sized capacitor to smooth the output into a stable voltage. The stable output voltage would then feed back to the fan to control its speed. The result would permit the pulsed motherboard signal to vary the MacPro fan speed.

 

[sanoayykk]

Try this. The pin 4 that you thought of as pwm is actually the Vcc.
That's why fan speed shifts as the changing of analog voltage of pin4.
On the other hand, pin 2 is the true pwm input. However it is not pulled up like ordinary fans so you have to add resistor manually in order to make the pwm function work on DOS/V mainboards.

 

[m2k]

Hi sanoayykk, I,m in the similar case, i have a MacPro 2009, that power supply fan death, and i cant find new Apple original fan to change. I decide use a Cougar vertex 4 pin fan, and i would like to know if i need use a some resistor to use speed control, or just i need change 2 and 4 pin.

I dont found any other page with this usefull information, thanks in advance

 

[iDVD]

@sanoayykk thanks for good info, finally I made mac pro fan working.
@m2k I think you in the same and different case in the same time. You want make opposite thing than I'm doing.

I have made a little research and found interesting thing. I made PWM fan generator(did not want to connect to my computer motherboard) for testing. Here are two diagrams who shows how I connected fan to PWM generator and power supply in two ways:

1. This diagram connected by this theory (GND = Ground; VCC = +12; O / P = Sense /Tacho; VM = PWM)


2. This diagram connected by this theory (GND = Ground; VM = +12; O / P = Sense /Tacho; VCC = PWM)


In both diagrams I used various resistors from 1k ohm to 100k ohm, because 1k ohm did not work for me(guessing because I connected m fan to my pwm generator). I used +5V to power PWM generator and macpro fan, want they work very quietly.

I don't know why and how it work in the both ways. How to know which way is good which is bad?

Then I control PWM signal up or down I heard strange sound going from fan. Can it be +5V fault? If I connected to fan to +12V it spins very loudly.

 

[ididit86]

@sanoayykk

Hi there,

So I have 5 mac pro 2006 fans that I want to use in a hybrid mac pro/hackintosh/atx build.

The fans are 0.75A fans.

I am trying to make sense of your post where you provided a very simple and apparently working solution by adding a 1k Ohm resistor between Vcc and PMW lines to the fan. My question arises when I consider which resistor I should get.

According to Joule's P=I*I*R to get the power capacity the resistor must have by providing the wattage it must dissipate. This would indicate, unless I am completely confused, that I would have to solder in a 1k Ohm resistor rated at >560ish watts? This doesn't make sense as I dont think I could even buy one with a rating like that nor fathom the heat this would generate.

Hopefully you can clear out any misunderstandings and recommend the safest and coolest option for a resistor in an application such as this. Hopefully you have time to respond sometime soon, as I am looking to complete this project this weekend... and if this wont work will need to order some fans such that they can be here by Saturday.

 

[ididit86]

@iDVD

Hi, you responded earlier to sanoayykk's post and said you tried his suggestion and "<you> finally made mac pro fan working". Could you offer the wattage rating of the resistor you used and/or any descriptions on your experience doing this? I have 5 mac pro fans I want to rig up in a hackintosh build.

 

[sanoayyk]

I forgot mentioning one trivial thing.
When off signal is applied to the PWM pin, the fan of MacPro stops spinning completely while normal ATX fan keeps spinning slowly. So when you put MacPro's fan in a ATX system, it is possible that fan speed control doesn't work well.
They are not totaly compatible.
I strongly recommend you not to use MacPro's fan as normal fan. If you want to do, pls make sure of raising your minimum fan power setting.


@ididit86
Hope this is not too late.
I guess you have been misunderstanding how these fans work.
In my method, the power for fan motor comes from Vcc pin of MB(pin2) and goes into pin4 of MacPro's fan.
It doesn't pass through the resistor. There is only about 12mA which will pass through, so you can use ordinary 1/4 watt or 1/6 watt resister.
Btw the extra resister is needed for especially my ATX motherboard. Since there may be some boards have pullup resister on themselves, you can start with just swapping pin4 with pin2.

@mk2
In your case, at least you have to change pins. If it doesn't work, think of add a resistor between GND and PWM control pin.
Sorry I am not able to tell what you have to do completely because I don't own a real Mac.

@iDVD
If your fan is from MacPro 2006, my schematic will be the best solution (resistor value may have to be adjusted), Cause I had analyzed it with Ammeter.
You said that diagram 1 also worked, I guess it is because that the signal output of your PWM controller have low output Impedance enough to drive a fan. Yeah it is not a wrong way from the viewpoint of electronics. But Vcc of a fan is not designed for being switched fast so it could harm fan or controller itself.
And why don't you supply 12V to the fan and set it slow by your controller?