21.5″ & 27″ iMac Hard Drive Replacement. + Overcoming Apple’s Engineering w/ Thermal sensors & Loud Fans

This story came as a suprise to us as usually Apple is one for using standard replaceable parts for it’s technologies. Hard Drives go out, RAM gets zapped, and you just install a newer / bigger-sized one. Most companies are afforded their proprietary rights in motherboards, LCDs, Inverters, etc. These latter objects can be replaced, but with some sense of knowing your getting into a game of needing the EXACT part. The car industry knows every bit of this sentence.

Macs and PCs get out of this game by offering upgrades that are standardized. A hard drive in a PC with SATA connections can be put into a Mac should you want. And while this is still true, the latest iMacs from Apple grumble, but allow it with a big noise. This noise is propagated from a thermal wire in the unit that has to be connected to a standard hard drive with proprietary firmware. If the firmware isn’t set, Apple’s own heat monitoring electronics don’t get the data that is needed and a fan in the unit revs from 1500 rpms up to 6000 rpms. This is bad and loud, especially if it’s your engine doing this.

So a handy computer repair person, like some of you, might try the repair as a standard knowledge set and be slapped in the face for doing just a standard repair.

As pointed out by the red arrows, Right, the Hard Drive and Thermal Sensor Wire can not only be a mis-match for your particular drive, but can also make your fans spin to terrific speeds.

 Hard drive replacement isn’t as hard as the picture above would lead you to believe. When doing a replacement with these new iMacs, it was specified to use the same brand of hard drive to give you a slight chance in overcoming issues. Now there is are two known pieces of software out there that can greatly help.


SSD Fan Control:  [ http://exirion.net/ssdfanctrl/ ] – Free. (test to see if it works on your mac first)

HDD Fan Control : [ http://www.hddfancontrol.com/ ] – Free to try for an hour; 30 $ charge.


7 thoughts on “21.5″ & 27″ iMac Hard Drive Replacement. + Overcoming Apple’s Engineering w/ Thermal sensors & Loud Fans

  1. The genius and pure passion that goes into creating these stories/facts are utterly amazing. Reading this assures me that having my computer fixed at your shop leaves me with an overall satifisfied-to-the-core feeling! Keep up the good work dudes!

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