ODD fan blowing constantly

Question

Level 1

7 points

ODD fan blowing constantly

I recently got a used iMac 21.5 inch Mid 2010 for free that had a failing HDD and a bad graphics card. Apple store wanted 600-800$ for the fix. So, I decided to venture on my own being that paying to fix a six year old iMac was almost the cost of a new one. I took apart the iMac and replaced the HDD with a Samsung 840 SSD that I had laying around and tried to bake the graphics card. The baking has seem to "fix" the graphics card for now and the SSD is working okay. I also ordered a mounting bracket for the SSD and the OWC in-line digital thermal sensor for iMac 2010 that connects to the sata port and provides compatibility for temperature readings. Link: https://eshop.macsales.com/item/OWC/DIDIMACHDD09/

My problem is that the ODD fan is blowing constantly. I've tried re-setting my SMC and restarting my PRAM/NVRAM. I downloaded Macs Fan Control and it shows the ODD fan at 0rpm even though I can clearly hear it on and blowing. I've tried unplugging the fan from the logic board and that does make it stop, but my temperature values all over start to creep up. My HDD and CPU fans seem to be fine and hover around 1100 and 1200 rpms and will respond to my controls in Macs Fan Control. The ODD, does not respond. It just keeps blowing regardless. Here is a screenshot:

I know that there is reported issues with the ODD fans blowing on high after upgrading to a SSD, but the in-line temperature sensor is suppose to correct that.

My questions then are: Is the ODD fan faulty? Is the logic board faulty? Did i short the logic board while disassembling it? Is there a way to check without ordering a fan only to have it not be the fix?

Thanks for the any guidance in advance.

Posted on Jul 17, 2016 6:07 PM

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Answer 1

kaz-k

Level 8

49,062 points

Jul 17, 2016 9:12 PM in response to bgreep1

Check with Apple Hardware Test if it's faulty.

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Answer 2

rkaufmann87

Level 10

140,478 points

Jul 17, 2016 9:19 PM in response to bgreep1

When you run AHT, run it in Extended Mode 2-3 times back to back. If you run it in the base mode that is a total waste of time. The reason to run it multiple times back to back is AHT is not the most reliable test and can miss errors after the first or second time, however when it finds errors they are correct. I suspect a fan sensor is shot or you have a bad or missed fan connection.

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Answer 3

bgreep1 Author

Level 1

7 points

Jul 18, 2016 9:42 AM in response to rkaufmann87

Thanks for the reply. I have tried to enter AHT but can't seem to get it to start. I held down option (alt on my keyboard) and D and nothing happens. I tried just pressing D and nothing happens. I read somewhere that the up key and D could work and nothing as well. I tried putting in my install usb and booting from the recovery partition to see if anything was in there but can't find it. My firmware password is turned off and I do not have a log in password. I tried using a bluetooth keyboard as well as a wired one with no difference in outcome. Any other suggestions as to what I could be doing wrong?

Thanks.

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Answer 4

bgreep1 Author

Level 1

7 points

Jul 18, 2016 9:46 AM in response to rkaufmann87

I will add that holding D down only does cause the computer to pause in the boot up for about 45 seconds or so, but nothing starts up and the computer just begins to boot like normal.

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Answer 5

rkaufmann87

Level 10

140,478 points

Jul 18, 2016 9:49 AM in response to bgreep1

Please carefully read Using Apple Hardware Test - Apple Support to get started using AHT. If you cannot access it, then I'd recommend taking it to an AASP that has the proper tools to diagnose it. If you don't know of any AASP's in your area please click https://locate.apple.com/country to begin finding one.

I know that isn't what you wanted to hear, however we often get do-it-yourselfers here that don't really have the proper tools to diagnose. Being a do-it-yourselfer can be good if you have a combination of the correct tools and knowledge, without both you can waste a lot of time and money which are both precious commodities.

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Answer 6

bgreep1 Author

Level 1

7 points

Jul 18, 2016 10:07 AM in response to rkaufmann87

Thanks again for the response. I would like to say I am more than your run of the mill do-it-yourselfer as I have built and repaired various pc's in the past. This is my first iMac though, so I do understand what you are saying. I don't have an apple store near me, so that would actually waste more of my time and money than simple googling in my free time. I may consider getting a new ODD fan for 30$ or so and see if that corrects the issue. If not, then the fan will go until it dies 🙂 It's better stuck on than off 😉

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