Chosen Solution
Hi everbody Today i decided to install an SSD (from apple) on the PCI port of my 27" iMac 5K late 2015 OK, followed the teardown, made sure I did nothing wrong on everything, I rebuilt but now when I try to boot —> nothing The LED of the motherboard —> Nothing, all the LED are off First thing I tried was to remove the SDD it remained the same, so this is not the SSD. Next I tried the power supply —> The big box for power in the iMac —> I put it in other iMac 27 2012 —-> the power supply is working !!! So guys, my iMac won’t boot and the LEDs are off (the number 1 too)! I tried many times everything, what is going on with it it is my mother board ??? I did nothing on it, I was soft and everything… Maybe there is a security on this model, maybe I have to push a button to unlock a security ??? Please help me ! The iMac was running fine, now the green LED is not even on! If LED #1 is telling me if the motherboard getting power from power supply why the led is off on my late 2015 if my power supply is working on other iMac 27 (late 2012) maybe cables on the power supply?
Sounds like you have a damaged logic board somehow. You talk about using an Apple SSD. Where did you get it? It could have been the wrong type which could have damaged things. At this point I think you’ll need to throw the towel in and put things back together so you can bring it into an Apple authorized service center or better yet an Apple Store. See if you can sneak it under a warranty repair or you’ll need to pay the bench fee.
