Chosen Solution
I recently replaced the fusion drive in my 2017 5k iMac with an SSD, following the iFixit guide. I’ve done this previously on a 2012 21.5 iMac which went off without a hitch. Unfortunately, after putting the screen back on, there’s no chime, no boot - zilch. Any ideas as to where to start? During the process, nothing was bumped, I didn’t move any logic board parts (just the left speaker slightly to the left to get to the 3.5 HDD bracket).
Perhaps you need to reformat the drive?
It most likely is trying to boot into the remaining SSD part of the the fusion drive which will not work nor will recovery drive. These will have been damaged as HD has been replaced bets thing is to get access to a Usb install drive and look at drives reformat and install on new drive
