Won't power up after switching out HDD
I have a late 2015 iMac 27" 1TB Fusion Drive.
I switched out the Seagate 1TB HD with a Samsung 1TB SSD and also switched the apple 32GB PCIe blade SSD with a Samsung 128GB SSD.
Before replacing the LCD screen I turned the computer on at the mains (started up without pressing the power button). I proceeded to reinstall OSX Sierra from a USB Flash Drive, while this was going on I reattached the LCD screen. Once OS-X was reinstalled I then migrated my info from my backup disk. All was working fine.
I powered down my iMac but now it won't power back up. I've checked the power wire from the power button which is fine and connected correctly, there is 1 LED lit on the logic board when plugged into the mains and all connections appear intact and fitted correctly.
Is this a good question?