Mac Mini Fans stuck on high

[waywardsage]

I have a 2.6 Core 2 Duo Mac Mini from a few years back that has worked like gang busters. All of a sudden, my fans are now stuck on high and will not cycle down. It sounds like a vacuum cleaner. I've reset the PRAM and SMC and it has not fixed the problem. I have also restarted several times.

I have not tried to open it up or install any ram or anything else. I think my mac mini is long out of Apple care. What should I do? Does any one know what this problem is?

 

[GGJstudios]

I have a 2.6 Core 2 Duo Mac Mini from a few years back that has worked like gang busters. All of a sudden, my fans are now stuck on high and will not cycle down. It sounds like a vacuum cleaner. I've reset the PRAM and SMC and it has not fixed the problem. I have also restarted several times.

I have not tried to open it up or install any ram or anything else. I think my mac mini is long out of Apple care. What should I do? Does any one know what this problem is?

1. Launch Activity Monitor
2. Change "My Processes" at the top to "All Processes"
3. Click on the CPU column heading once or twice, so the arrow points downward (highest values on top).
4. Click on the System Memory tab at the bottom.
5. Take a screen shot of the whole Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
6. Post your screenshots.

 

[waywardsage]

Here you go.

 

[GGJstudios]

Here you go.

Read step #2 and try again.

 

[simsaladimbamba]

Read step #2 and try again.

You should bold step 2, maybe link to this nifty image if you want, as you often have to post the above quoted post.

 

[waywardsage]

Is this correct?

 

[zachnelson]

Is this correct?

Looks good, no processes taxing the CPU badly.

Download http://islayer.com/apps/istatpro/

It's a dashboard app, and screen shot the temperatures.
It should also be able to mess with fan speed via the fan API, however it might not work for you.

 

[Acronyc]

The fan connection cable could be loose. iFixit has a good fan replacement guide you could follow to see if the cable is loose or broken. I think that's the right guide for your mini, but you might want to check and make sure.

It could also be the thermal paste on the CPU or the heatsink temperature sensor. I got a 2006 Core Duo mini for about $50 locally and it had the constant fan problem. I opened it up and the fan sensor cable was all okay, but it still ran at the highest speed constantly. So I removed the CPU, applied some new thermal paste, made sure the heatsink temperature sensor was snug, turned it back on and no more loud fan! After running it for a few days to make sure it didn't come back, I tossed in a 320GB hard drive I had lying around, 2GB of RAM, did a fresh install of SL, and sold it for $250.

Definitely check out the istatpro dashboard app. I used it to find out the heatsink temperature sensor was giving a reading of 126C all the time, which helped me isolate the problem.

 

[waywardsage]

Hmm...I took it into the Mac "Genius Bar." The genius called me back this evening and left a message saying that heat sync and logic board are one piece and that they need to replace the entire logic board. Since I've never taken the Mini apart, I guess I have to take his word for it?

How complex would this be to fix for myself? Is it even worth fixing?

 

[GGJstudios]

Hmm...I took it into the Mac "Genius Bar." The genius called me back this evening and left a message saying that heat sync and logic board are one piece and that they need to replace the entire logic board. Since I've never taken the Mini apart, I guess I have to take his word for it?

How complex would this be to fix for myself? Is it even worth fixing?

It would be pretty complex, even if you could get the parts (which I doubt). I wouldn't suggest attempting that. Your best bet is to bite the bullet and have it repaired.

 

[waywardsage]

I decided to put the repair costs toward the purchase of a used Mac Pro. I've been needing one anyway. So this sort of just forces the issue. It's lame that I have a crippled mini though Not sure what to do with it now.

Suggestions?

 

[waywardsage]

The fan connection cable could be loose. iFixit has a good fan replacement guide you could follow to see if the cable is loose or broken. I think that's the right guide for your mini, but you might want to check and make sure.

It could also be the thermal paste on the CPU or the heatsink temperature sensor. I got a 2006 Core Duo mini for about $50 locally and it had the constant fan problem. I opened it up and the fan sensor cable was all okay, but it still ran at the highest speed constantly. So I removed the CPU, applied some new thermal paste, made sure the heatsink temperature sensor was snug, turned it back on and no more loud fan! After running it for a few days to make sure it didn't come back, I tossed in a 320GB hard drive I had lying around, 2GB of RAM, did a fresh install of SL, and sold it for $250.

Definitely check out the istatpro dashboard app. I used it to find out the heatsink temperature sensor was giving a reading of 126C all the time, which helped me isolate the problem.

iStat says the chip is at 103 degree's F. The Genius tech ran some diagnostic that said that it couldn't read the heat sync on the chip. It all sounds too fishy to me. Is there a diagnostic app i can download to trouble shoot this?

 

[Acronyc]

iStat says the chip is at 103 degree's F. The Genius tech ran some diagnostic that said that it couldn't read the heat sync on the chip. It all sounds too fishy to me. Is there a diagnostic app i can download to trouble shoot this?

If there's no heat sink reading I'd imagine that the heat sink, logic board, or connection between the two is bad. I'm not sure of any specific troubleshooting diagnostic app for this, all I've ever used is iStat.

I'm not sure about C2D minis, but on the Core Duo mini I took apart I can guarantee that the heat sink and logic board are not one piece. The heat sink is attached to the CPU with plastic pins and to the logic board with a simple plug. If your mini has a socketed CPU you can definitely take off the heat sink, but if its soldered I'd imagine you'd need a new logic board.

Taking minis apart isn't too bad, and I'd suggest checking out iFixit for guides on your specific model if you try to go about the repair yourself.

 

[waywardsage]

I took it apart entirely. But I couldn't find a heat sync fix on ifixit. How do you take the heat sync off the chip?

 

[bdahi]

For those who have recently opened the case

This thread is a bit old but I had a similar problem and couldn't find the answer her. Then I figured it out myself and wanted to share it with future visitors:

I recently upgraded my RAM and HDD of Mac Mini 2GHz Core 2 Duo and after putting everything back together, the fan was stuck on high even if the internal temperature was about 40ºC all the time. The problem happened to be the fan regulator cable that is the first thing I disconnected after opening the case. It's located at the front side of the box, under the opening for the DVD player. It needs to be connected to the motherboard.

Hope this helps someone out there.

 

[Rizvi1]

This thread is a bit old but I had a similar problem and couldn't find the answer her. Then I figured it out myself and wanted to share it with future visitors:

I recently upgraded my RAM and HDD of Mac Mini 2GHz Core 2 Duo and after putting everything back together, the fan was stuck on high even if the internal temperature was about 40ºC all the time. The problem happened to be the fan regulator cable that is the first thing I disconnected after opening the case. It's located at the front side of the box, under the opening for the DVD player. It needs to be connected to the motherboard.

Hope this helps someone out there.

Same here. I think it was almost a year ago that I took out the bad hard drive of my A1176 1.83ghz Core 2 Duo Mac Mini and put a new one in. But in doing so I hadn't re-connected the hard drive thermal sensor cable connector (see Step 9 here: http://www.ifixit.com/Guide/Installing+Mac+mini+Model+A1176+Fan/1107/2 ). Today I popped the lid off via the putty knife and then just reconnected that cable. I didn't have the tweezers on me so I just messed with it via my hand until it went in.

 

[xArtx]

heat sync and logic board are one piece and that they need to replace the entire logic board.

What does that have to do with the fan?

What did they suggest went wrong with a piece of aluminium extrusion?

I took it apart entirely. But I couldn't find a heat sync fix on ifixit. How do you take the heat sync off the chip?

You could try searching for "heat sink" instead.

 

[Mr. McMac]

This is my 2007 Core 2 Duo 1.83gHz Mac mini. I opened mine to add RAM and install a larger HD. I didn't mess with the CPU heat sink. From the picture you can see it's held down with 4 spring loaded locking push pins. You probably need to release them from the bottom of the circuit board to remove it. It should be easy to do.

 

[danjrael]

Fan Control Utility

I recently bought a 2006 Mini Core Duo, 1.83GHz with 512mb RAM. I opened the unit up and changed only the RAM to 2GB, and when I reassembled and started up, the fan begins to run at full speed, over 5400rpm. What is working as a temporary fix until I can re-open the unit to apply thermal paste and check the connections, is to install a fan speed utility called 'Macs Fan Control', downloadable here:

http://www.macupdate.com/app/mac/47386/macs-fan-control

The utility reports cpu, heatsink, and hard dsk temps between ~90 and 120 F with only warm air issuing from the fan exhaust vent.

I set the minimum fan speed at around 3500, and the max temp at 140 degrees F. Fan immediately responds to run at the slower speed, with temps remaining in the 90 to 120 F range, and quiet way down. I can hear it fluctuating up and down in response to temp changes, so I know the sensor is working. There is a choice between having the utility respond to hard disk, cpu, or heatsink temps. I used the one labeled 'cpu diode'.

Will report back here with what happens after I service the interior again.

Here is the link to the excellent YouTube/iFixit video I used to dismantle the Mini:

https://www.youtube.com/watch?v=vyGUVhT4AdY