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iMac does not boot after repair Hi, Because the GPU was not working properly i decided to switch it for a new one. I chose a NVIDIA GeForce GTX 780M. Replacing the card was easy and using a USB drive to boot into linux and using SSH to flash the card worked perfect. The 3 led’s on the logic board where on! After reinstalling the screen the iMac would not boot. So far I did the following: Reinstalled the original GPU Switching the RAM Disconnecting all devices external and internal Switching the PSU Switching the logic board But still the iMac wil not boot. All parts I used are working properly in other iMac’s. When I start the iMac no chime and after a while the fans spin up to full speed. Anybody know what other options I have? The only thing I did not replace are the fans and the power button.
Sounds like you used a non-Apple MXM card as you stated you needed to flash the board. I would say you likely didn’t flash it with the correct image or the OS doesn’t have the needed driver. Are you able to boot up under Safe Mode? Restart the system and using a USB keyboard press the Shift (⇧) key. Reference: Mac startup key combinations
