After buying a new Seagate 2TB Hard Drive for my iMac, I went about the job of installing it. I was a bit worried when I heard you had to take the glass off the front, but it didn’t turn out to be much of a problem. What did turn out to be a problem was the fact the hard drive fan started spinning at maximum rpm as soon as the new drive was hooked up. I’d read beforehand that Apple use the temp sensor built into the hard drive to monitor and adjust fan levels. With this in mind I’d bought the exact model Seagate that Apple used back in 2009. Well it turns out that without being flashed with Apple’s own firmware, the drive uses the pin-outs for drive rpm and not temperature. Talk about annoying!
I’m not giving up hope just yet though. My next plan is to order a temp sensor used for the optical drive. In theory this can be swapped out for Apple’s own solution and your iMac will be back monitoring to its hearts content.0