4-pins fans?

fabre · Post by **fabre** » Thu Sep 21, 2006 8:33 am

My motherboard an Asrock 939Dual-VSTA can control the cpu fan speed but requires a 4-pins fans.

I checked my usual pc shops but couldn't find any 4-pins fans, and the stock cooler that came with my cpu was a 3-pin fan.

Is it possible to buy 4-pins fans?
Alternatively is there a trick to get a Nexus fan to be controlled by the motherboard?

I already tried Speedfan and it can't change the fan speed on my motherboard.

mbetea · Post by **mbetea** » Thu Sep 21, 2006 9:53 am

It's not automatic, but you could try using a Zalman FanmateII:
http://www.performance-pcs.com/catalog/ ... ts_id=1767
The only 4pin fans I'm aware of (that you can buy at least) are JMC:
http://www.performance-pcs.com/catalog/ ... ts_id=3977
Though I don't have any experience with them.

jhhoffma · Post by **jhhoffma** » Thu Sep 21, 2006 12:44 pm

4pin fans are for built-in PWM fans where the mobo has built-in software/firmware to control the speed. Which is probably why the mobo won't work with Speedfan. It doesn't have PWM ability so it requires the fan to.

Perhaps one of the other fan headers on your machine has a PWM circuit and 3-pin headers? There's no rule on where you have to connect your CPU fan to (at least most of the time). Then you can connect any ol' 3-pinner to the mobo and use it for your CPU fan (of course it won't register as that in the BIOS, but who cares?)

Dave S · Post by **Dave S** » Thu Sep 21, 2006 5:23 pm

I had a similar question, and don't believe there is any direct answer
http://forums.silentpcreview.com/viewtopic.php?t=33911
I didn't find any pwm fans or enthusiast heatsinks with pwm fans except these Nexus products:
http://www.endpcnoise.com/cgi-bin/e/std ... -7750.html
http://www.endpcnoise.com/cgi-bin/e/std ... -7750.html
Direct mobo control over fan speed could be optimal, but a potential drawback of pwm fan speed control is that it may make a fan "tick" as the Pulse is Width Modulated on and off.
There is more info in other forums, this one is encouraging: http://forums.silentpcreview.com/viewto ... sc&start=0

Dave S · Post by **Dave S** » Thu Sep 21, 2006 5:28 pm

Sorry, correcting my own posts is becoming a personal style...
mbetea gave you a good source, I may buy one of these fans.

Thanks mbetea!

fabre · Post by **fabre** » Thu Sep 21, 2006 5:45 pm

Thanks guys

I think I am going to order the 92mm version of the fan mbetea suggested

For once shipping to canada is reasonable.

fabre · Post by **fabre** » Tue Oct 10, 2006 9:58 am

Finally received the 92mm JMC fan, but PWM doesn't work fan run at full speed all the time.

How can I tell if the fan is properly wired?

mbetea · Post by **mbetea** » Tue Oct 10, 2006 10:34 am

Hmm, I remember reading a while back on a couple forums people having this problem. It turned out JMC shipped a number of fans that were not wired right at the connector. Trying now to find the forums where a couple people figured out which wires were switched. But this should give you something to check the wires against:
http://www.jmcproducts.com/products/pwm ... ndex.shtml
Hope this helps.

Edit: I found this: http://forums.silentpcreview.com/viewto ... 17a5a409f5
Not what I was looking for but should help, pay attention to gilmanw's 4th post.

fabre · Post by **fabre** » Tue Oct 10, 2006 10:45 am

Interesting the diagram show

GND (-): Black
PWR (+): Red
Optional Signal (xxx): White
Control (PWM): Blue

But if I look at my fan wires I have

Black
Yellow
Green
Blue

In that order at the plug.

But now that I am thinking about it, if Blue and white were reversed would the Bios and speedfan be able to report accurately the fan speed?

fabre · Post by **fabre** » Tue Oct 10, 2006 10:58 am

Here is gilmanw's post you mentioned

The fan arrived very quickly and appeared to be in good condition, but it did not work when I initially plugged it in.

However, luckily I noticed that the fan's 4-pin connector didn't look quite right. Turns out the wires were in reverse order. From pin 1, the signals to the 4-pin connector should be: Gnd, +12V, Sense (rpm signal), and PWM control. At least on the unit I received, this corresponds to Black, Red, Blue, and Yellow (I confirmed this by peeling back the label on the pin hub and observing which wires were connected to the contacts labelled: G, V, S, and P respectively). With the aid of a small screwdriver, I removed and repositioned the pins in the connector in the right order and on the next try the fan spun up.

The JMC distributor later confirmed that I identified the labels correctly. He also confirmed that the 92mm fans seem to always need some "attention" (his words), but claimed the other sizes always seem fine. Does raise serious concerns about the QA of their manufacturing line.

In my case the fan run and I get rpm reading in both Bios and Speed fan but motherboard PWM doesn't work. So I am not entirely sure if the issue come from the fan or motherboard.

Dave S · Post by **Dave S** » Tue Oct 10, 2006 1:19 pm

I'm using the 120mm version of this fan on my Intel system. I've read in your motherboards manual that it has the AMD Cool and Quiet feature. Have you enabled this? It may be needed, Just a guess. Mobo page with link to manual: http://www.asrock.com/product/939Dual-VSTA.htm

slimeballzz · Post by **slimeballzz** » Tue Oct 10, 2006 3:08 pm

What's the difference with a PWM control input and using Speedfan?

fabre · Post by **fabre** » Thu Oct 12, 2006 8:53 am

Ok problem fixed, fan was fine it was the quiet fan bios function that wasn't working, I contacted Asrock and they sent me a "special" version of the bios (1.30A)
It now works and instead of having options of slow/medium/fast for the Target Fan speed, I have a range of 10% to 90%

slimeballzz wrote:What's the difference with a PWM control input and using Speedfan?

Well in my case the board support pwm so with a 4pin fan I can set a target temperature and fan speed and the fan speed will adjust automatically accordingly. And speedfan can't adjust fan speed on this board which I don't mind since having the fan controlled by the bios is safer.

puscifer · Post by **puscifer** » Sun Oct 22, 2006 5:34 am

I'm a bit lost here.. in the process of upgrading to a P5B-del. I wanted to control the tricool in the P180. Since they're 4pin i'm guessing they're PWM (what does PWM stand for, actually?) so can i hook them to the mobo with 4pin>3pin conectors and use speedfan? Will I get their rpms?

nici · Post by **nici** » Sun Oct 22, 2006 6:04 am

PWM stands for Pulse Width Modulation. Basically you chop up DC to pulses, and depending on how wide the pulses are and how there is 0V between the 12V pulses determines how the fan sees the voltage. 50% PWM would be about half the voltage to the fan in theory at least. For half the time the fan gets 12V, and for half the time it gets 0V meaning an average of "6V". That's a really simplified explanation, i bet wikipedia has a more detailed description.

And the Tri-Cools don't have RPM monitoring.

puscifer · Post by **puscifer** » Sun Oct 22, 2006 7:24 am

Damn.. Why are they 4pin? :/ Without the rpm monitoring it's definately not very handy. The antec manual 'said' i could adjust their voltage, can i still do it with that thermal %'s system in speedfan? Or i'll have to shell out another â‚¬60 in 4x S-flex (1600rpm)?!

pyogenes · Post by **pyogenes** » Sun Oct 22, 2006 9:26 am

puscifer wrote:I'm a bit lost here.. in the process of upgrading to a P5B-del. I wanted to control the tricool in the P180. Since they're 4pin i'm guessing they're PWM (what does PWM stand for, actually?) so can i hook them to the mobo with 4pin>3pin conectors and use speedfan? Will I get their rpms?

The listed 4-pin connectors is a different 4-pin connector from what is talked about in this thread. They mean the much larger 12V Molex connectors you use to hook up IDE drives (the are not PWM fans). Also, the tricools have a swtich on them that can change the speed between 3 settings, but not very convenient if you wan to change fan speed on the fly.

slimeballzz · Post by **slimeballzz** » Sun Oct 29, 2006 11:44 pm

If there is already 12V going into the fan, then what does the PWM wire do?
(or what type of signal goes into it?)?

orihara · Post by **orihara** » Mon Oct 30, 2006 9:03 am

The PWM wire carries a high frequency signal with a duty cycle between 0 and 100%. The voltage the fan motor recieves is modulated by this signal. This is done so that the RPM sensor doesn't have a modulated voltage signal, which could screw the results.

slimeballzz · Post by **slimeballzz** » Mon Oct 30, 2006 4:40 pm

orihara wrote:The PWM wire carries a high frequency signal with a duty cycle between 0 and 100%. The voltage the fan motor recieves is modulated by this signal. This is done so that the RPM sensor doesn't have a modulated voltage signal, which could screw the results.

So the PWM overrides the 12V?
Can't I just put a square wave input into the 12V line and modulate the duty cycle?

orihara · Post by **orihara** » Mon Oct 30, 2006 11:53 pm

slimeballzz wrote:
orihara wrote:The PWM wire carries a high frequency signal with a duty cycle between 0 and 100%. The voltage the fan motor recieves is modulated by this signal. This is done so that the RPM sensor doesn't have a modulated voltage signal, which could screw the results.
So the PWM overrides the 12V?
Can't I just put a square wave input into the 12V line and modulate the duty cycle?

Err...

The reason for this is to make it simpler for the MB to be able to read off the RPM reading while the fan isn't going at 100%. If the 12V is modulated directly, then the RPM reading can be off because the sensor doesn't have power when it should be reading a pulse.