Using MAC Pro Case fans for case Mod??

[blackknight]

Aqua, what RPM are the fans when you do that? When I had 12V on Pin 2 and 5V on Pin 4, they ran at about 1100-1200 RPM. If you want them to go a little slower, you can hook the 3.3V line from a sata connector to Pin 4 and it'll run them at about 800-900 RPM. That's the simplest speed reduction method. It's funny that 3 Delta AFB1212HHE standard fans are about the same price as one Apple AFB1212HHE-5k75 fan and have nearly the same specs, just at lower current requirements. I might go that route at some point as they are basically the same fan. They only require .45A and can be controlled like any other 3 pin fan. You could even pick up one of these: www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=36_48&products_id=22223 and possibly control all three and still have power to spare.

[aquamac]

Blackknight,

I am not sure of the RPM @ 5v but they are reasonably quiet. I like the idea of 3.3v though and had not thought about that. Do they still boot up OK at that voltage. They (120mm) do seem to need a fair bit of juice to get things moving!

[blackknight]

They start spinning up with 1.8-1.9V. I suggest running a wire from pin 3 to your motherboard for tach sense. The 3.3V should be used with 12V on pin 2 and 3.3V on pin 4. I think this is the reason that they still start with ~2V as they still have voltage coming from pin 2. Don't ask me why, I only know this from experimenting.

[aquamac]

Hey Blackknight,

As you suggested, i just connected my 120 mm Mac Pro case fans as follows using a Sata lead from my power supply which also has a 3.3v lead and I am really pleased with the results.

PIN 1: Ground
Pin 2: 12 v
Pin 3: To sense on MB (Yellow Lead) I can see the speed in around 1045 RPM in the bios.
Pin 4: 3.3v (Orange lead on Sata)


||..............................||
||___1___2___3___4___||

View looking at the bottom of plug.

It would be neat to come up with a circuit to control this from the motherboard. I will do a better picture in a while.

[blackknight]

Glad you like it. I actually used a sata connection to run power wires to my front panel board since it had the 4 wires I needed (12V, 5V, 3.3V and GND). It kept me from having to hack an ATX extension.

I think you'd need something like an arduino or other microcontroller to do it properly as the current draw of these fans is just way too much for a motherboard. You need to program a controller to take a 0-12V and control another power source from 0-12V. I found that if you run 12V to pin 4, it doesn't burn the fan out. I think Shanky hooked 12V to pin 1 and pin 4 which would probably do it. Anyways, to control 3 or 4 fans that require .75A each would take a controller with some serious power output. Good luck and I'll test what you come up with as these fans are not in use anymore until we figure something out.

[samwiches]

I just picked a AFB1212HHE-5K75 to use on an ASUS P8Z68-V PRO/GEN3, but it doesn't seem to work at all.

Tried testing it by using the Green wire as 12v and Black as ground and it does nothing. Was that the wrong idea?

It's possible I had it backwards but the pins are back out of the connector now. Tried again and still nothing.

[reddrag0n]

Found this in a different forum. Hopefully it helps you guys out...

Ok, I did some experimenting today. The pinout for the fans looking at it from the end of the connector looks like this:

|______|
| 1 2 3 4 |

where the top spikes are the key tabs on the connector. Pin 1 is ground, pin 2 is 12V power, pin 3 is the Tach sens., and pin 4 is the control pin. I supplied 12V to pin 2 and slowly increased the voltage to pin 4 up to 12V without frying the fan at all. This means that if you make a connector that is exactly the same as a 3 pin fan (a normal 3 pin to 4 pin molex adapter) and connect it to the PSU molex connector (these fans draw a lot of current so don't power it from the motherboard) and run two more wires to the tach and voltage wire from the motherboard to the tach and control pins of the fan, you would have control.

That being said, these fans run really fast at a full 12V and even down to 5-6V and are very loud. That's where the ULNA adapter comes in. These are simply just a 3 pin extension with a resistor inline on the power wire. There are two adapters that came with the fan and one is 150 ohm, the other is 50 ohm. These will reduce the 12V output of the motherboard header to about 5-6V or 3-4V depending on the adapter. This is a much more reasonable speed.

They are very quiet up until about 1000-1100 RPM (about 2.5V on the control line) but the specs for these fans say they are 3300 RPM fans. They move 130 CFM at 44 dB, but utilize .75A each. I also hooked a multimeter up to them to measure current draw and found that they draw that current on the control line. The problem is that the motherboard just can't handle that much current. I've also measured the current on the 12V power wire (pin 2 in the above description) and found they use about .2A on that line, but reducing the voltage to pin 2 doesn't change the speed of the fan.

My conclusion seems to be that these will just have to be manually controlled. I built a LM117T-ADJ circuit with a potentiometer that varies the voltage between 2.5V and 5V which does a decent job of controlling them. I used the output of the circuit to go to the control wire. This lets the fan range from 800 RPM to 1100 RPM and at all ranges move lots of air at near silent operation. I personally wouldn't spend $40-$50 on these as they are too difficult to control, but these are basically the same fan: www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=36_403&products_id=24322 for $16. They have almost the same exact model number (last four digits are different), but when I compared them to the specs here: www.excesssolutions.com/cgi-bin/category.cgi?item=ES5358, they're basically the same. The difference is that the non-Apple fans are easier to control.