iMac not starting after upgrading CPU and pci-e storageHi, I attempted to upgrade my 2019 5k 27” imac by changing the CPU and the pci-e storage, and replacing the sata disk with...
Ответ на "iMac 2019 27" CPU change"Try reseating the RAM first, then the PRAM before taking it apart again. I had this similar problem.
Ответ на "iMac not starting after upgrading CPU and pci-e storage"So to close this off, I managed to fix the iMac but there were two separate problems. (1) The first problem, LED 2,3 were green, but not the others, was solved by reseating the RAM. I then tested using the display before seating the parts back in place, but when I put the display back after everything was screwed in, LEDs 1,2,3,5 lit up, there was no backlight but I could use an external monitor and see the apple logo in the display when I shone my camera flashlight on it. (2) This became an Odyssey. LEDs 1,2,3,5 lit up when the Mac was powered, and LED 2 when power was connected but the machine was off. I replaced the display, logic board and power supply at the expected cost but nothing worked. A final suggestion from The Bookyard suggested changing the eDP cable, as it was the only common part left to the new and old components. And hey presto, the backlight worked. The say that the backlight failure and the eDP cable have been implicated before and in my case that was the cause. (3) The LED diagnostics...