Mac Mini (early 2009) Fan Issue

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Level 1

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Mac Mini (early 2009) Fan Issue

Hey

I bought a refurbished Mac Mini (early 2009) back in May. I have had this problem with the fans running at high speed (5000 RPM +) pretty much from the beginning. I upgraded the hard drive and RAM and put everything back, but the Mac Mini always thinks that it is 259 degrees Fahrenheit, making the fans run at high speed. I have had to run the SMC fan control and an Automater program that limits the fan speed, but now I want it to work correctly. Can I replace the hard drive temp sensor, or is there anything I can reset to get it reading correctly?

Thanks

Message was edited by: aquaxtreme

Posted on Oct 9, 2009 1:50 PM

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Answer 1

Boece

Level 5

6,264 points

Oct 9, 2009 3:11 PM in response to aquaxtreme

Did the fan (there is only one) always run full blast, even before your opened the Mini and did the upgrades? Or did it take some time running before the fan would speed up?

There are three general causes for the fan running fast:

1) Insufficient access to room temperature air -- usually due to the Mini being enclosed in furniture, sitting on other heat-producing equipment, or clogged air vents in the Mini. This will usually cause the fan to run fast after the Mini has run for a few minutes, but not immediately on startup.

2) Fan control wire not re-attached after work inside the Mini. This will cause fan to run full speed all the time.

3) PMU reset procedure wrongly applied to an Intel Mini. Only PPC Minis get he PMU procedure. Intel Mini's should have the SMC reset instead. Applying the SMC reset can usually undo the damage. When the PMU procedure has been applied to an Intel Mini, the fan will run full speed all the time.

The SMC reset is described here:

http://support.apple.com/kb/HT1543

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Answer 2

aquaxtreme Author

Level 1

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Oct 9, 2009 4:08 PM in response to Boece

Thanks for your response.

When turned on, the Mini's fans immediately speed up to full power. The Mini is not hot or getting hot, it just thinks it is for some reason. By time I log on, I can check iStat to see that the temp is 259 degrees. I reopend the Mini a couple weeks back to make sure that the cable was attached, and it is and is not pinched or anything like that.

I will try the SMC reset that you linked to. If anyone else has input, please do so.

Thanks

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