CONFIRMED - Mooing sound caused by intermittent fan

Question

Level 2

419 points

CONFIRMED - Mooing sound caused by intermittent fan

Since so many people talk about the mooing sound, I decided to take matters into my own hands.

I took apart a MacBook (I'm not gonna say who's macbook. 😉 and ran the computer WHILE the cover was off. So I had a clear view of the MacBook's one and only cooling fan. The result?

The fan turns on and off at exactly the same interval as the mooing sound. The noise does NOT come from a faulty fan or any kind of physical rubbing. It comes simply from the airflow turbulence created by the fan.

I took VIDEO FOOTAGE of the fan turning on and off at exactly the interval of the mooing sound. Once I figure out how to post a video link, I'll upload it for you all to see. I hope the sound quality is good.. we'll see.

At exactly 67C (CoreDuoTemp) the fan turns on/off, on/off, and so on.

Mac Mini 1.58Ghz (OCed!) / MacBook black, Mac OS X (10.4.4), 60GB 7200RPM Hitachi HD.

Posted on May 23, 2006 4:56 AM

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Answer 1

Yongwon Lee Author

Level 2

419 points

May 23, 2006 6:31 AM in response to Yongwon Lee

HERE'S THE VIDEO!

http://video.google.com/videoplay?docid=-4490733167064230159

A small payback for this helpful forum community. I made the video myself, and I have all the copyrights, yadayada... You are welcome to share/download/show it freely.

Enjoy!

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Answer 2

May 23, 2006 6:23 AM in response to Yongwon Lee

Very nice work!

Thanks for the video.

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Answer 3

Xipher

Level 1

5 points

May 23, 2006 6:30 AM in response to Yongwon Lee

So if the "mooing" is caused by the fan turning on at 67.0 and turning off at 66.9 (which is stupid IMO), this could easily be patched in a firmware update.

Lets just hope Apple does something about it.

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Answer 4

kaidomac

Level 1

55 points

May 23, 2006 6:38 AM in response to Xipher

Excellent video Yongwon Lee! The sound reminds me of my old remote controls cars I had when I was a kid 🙂 That should be a simple software fix, if the fans are controlled by software. When it gets to a certain temperature, my Gateway laptop's solution is to kick the fans on for about a minute and a half, then shut off if the temperature decreases. I don't get any of that schizophrenic fan activity that way.

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Answer 5

May 23, 2006 7:20 AM in response to Yongwon Lee

Just to give you a little more peace of mind after pulling that off for us -- your warranty is most definitely NOT voided by simply opening the case. Only if you broke something...and even then, it's not "void," they just won't fix the damage you made 😉

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Answer 6

May 23, 2006 7:35 AM in response to Yongwon Lee

Very nice work. So as I understand it, the mooing is just the fan starting and stopping. Does the fan not moo when it just kicks on and stays on for a more sustained period of time or does it just spastically start and stop without really staying on? For instance, what is the fan doing when the MB is under 100% CPU load and reaching toward temps in the 80's?

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Answer 7

May 23, 2006 8:00 AM in response to Yongwon Lee

The mooing sound just gives it more personality, LOL

Not much of a problem if you love cows! It's dogs for me. Can I get one that barks? Yongwon, you seem pretty good at this computer stuff, can you make my macbook bark?

Really though, great research and video.

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Answer 8

kjk

Level 4

1,323 points

May 23, 2006 8:30 AM in response to Yongwon Lee

nice work yongwon!!

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Answer 9

st8ic

Level 1

80 points

May 23, 2006 9:50 AM in response to Yongwon Lee

hmm... Google Video says that file is not avaliable.

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Answer 10

Yongwon Lee Author

Level 2

419 points

May 23, 2006 12:58 PM in response to Yongwon Lee

Since some people have issues with Video.google not working, I uploaded the file to YouTube as well. Here's the link!

http://www.youtube.com/watch?v=vEPzlIkBnGs

Once again, you're welcome to share the link and video. Please don't upload it to another site, I'll look into that if required. (But sending the link around is fine. THanks for putting this on "Digg.com")

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Answer 11

May 23, 2006 3:11 PM in response to Yongwon Lee

Thanks! You are the man

Paulo Lemos

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Answer 12

May 23, 2006 3:47 PM in response to Yongwon Lee

Excellent YWL, good work. Now the onus is on apple to release either firmware or an updated k.ext.

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Answer 13

May 23, 2006 9:19 PM in response to Eric Bostrom

Can you confirm that when the fan is running continuously (say above 70 degrees) that the mooing doesn't occur? if it does occur when it's running continuously I don't see how it will be fixed.

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Answer 14

pentae

Level 1

0 points

May 23, 2006 9:58 PM in response to Yongwon Lee

Nice work mate! Good on you.

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Answer 15

May 23, 2006 9:58 PM in response to bryan49ers

The mooing is a problem because the fan hits a point where it kicks on and off, on and off rapidly. the moo sound is the fan spinning up then down, not spinning up and staying up. if they increased the temperature limit before it turned on, it would turn on and stay on longer instead of fluttering between on off status and mooing.

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