For the 20 iMac systems, the Western Digital hard drives Apple used have swapped connections for the temperature feedback control, so while you may have seated the sensor connection into the same socket of the hard drive according to the instructions of a reputable guide or two, you may simply have swapped the poles of this connection. This detector has relatively sensitive connections, so even if properly seated in its socket during reassembly, it may have an improper connection that results in the fan blaring at high speeds since no feedback is present.Īnother issue that Other World Computing outlines, is where the temperature feedback for the new hard drive itself may be improperly connected.

In order to get to the drive, one of the steps in disassembly is to remove a temperature sensor cable that provides feedback if the LCD display gets too hot. Recently the Mac-centric retailer and supply company 'Other World Computing' outlined a potential issue where people upgrading their iMac's hard drives may simply have incorrectly reassembled a temperature feedback control when reassembling their systems.

Some have speculated that the iMac may require special firmware from Apple in its hard drive to prevent the cooling fans from being maxed out however, this may also not be the issue at hand. Since the fan speeds and temperature feedback are managed by the Mac's system management controller (SMC), if this happens, the first course of action may be to attempt an SMC reset however, this may not fix the problem. However, some people who have done this have found their iMacs no longer give a relatively noiseless computing experience, and end up blaring their cooling fans at the highest speeds.

While not a trivial task, it is definitely doable with the proper know-how, such as following some of the guides available at iFixIt and other sources. In order to replace an iMac's hard drive, you have to open the front of the system by using special tools to lift off the glass, then get underneath a number of components to reveal the hard drive bays. Are your iMac's fans blaring at full speed after having upgraded or replaced its hard drive? If so then you may have overlooked a simple detail or two upon reassembling your system.

New hard drive for imac