Replacing the HDD for an SSD on an Apple IMac 21,5 4K Late 2015
The entry level IMac 21,5 4K Late 2015 has an HORRENDOUSLY SLOW 1TB 5400 RPM hard drive, that made the whole experience of using the computer, an absolute pain. We got this computer as a replacement for a white polycarbonate Macbook, that turned out to be running a lot faster than the new computer (since I had installed a Samsung EVO SSD 1 TB a year ago) - I wanted to take the SSD out of the Macbook and put it into the new IMac
I searched about replacing the hard drive on this machine, and landed on iFixit's guide on how to replace the hard-drive.
It was exactly what I needed, BUT... there was a subtle difference that I want to highlight. The SATA connector is now in one piece, so whereas it was easy to disconnect (I just pulled the hard drive out and that's it) it was IMPOSSIBLE to re-connect without disassembling the left speaker.
Yes! - In order to complete the hard-drive replacement without any hitches, take the time to remove the left speaker when you remove the hard drive. For that you need to disconnect the two wire connector of the power switch (to be found in the lower left corner of the power logic board. Then, disassemble the fan and take it off (remember to disconnect it's power cable from the logic board) and finally take the speaker off. This will allow you to re-connect the new hard drive without any problem.