I recently purchased 2 iMAC 27" 5K 2019 3.6 g i9, each with 128gb of RAM from OWC, and the experience has been a nightmare. I purchased both to replace 2 2008 iMACs in my music studio. So part of the process was to open all four computers once the new ones arrived to swap drives and NVME drives. The first thing that went wrong was that the adhesive tape they sold me failed on all four machines. Three of the four we caught in time and the fourth (New One) was not so lucky. Screen cracked when it fell off but is still usable. Just received the new screen (not from OWC) and decided to make the switch this past weekend. I removed the tape holding the screen on the good one, on Friday night and when I went to do the actual install on Saturday morning, the screen was lying on the desk again fell off. Got lucky and the screen did not crack. Upon replacing the screen, the computer would not boot. No startup chime and black screen. Interesting note here is that every night I turn off the power to the studio so there was no power on either computer when the screen fell off. For the 5 Test LED's, # 2 is lit as long as the unit is connected to power. Upon pressing the power button, LED #3 illuminates, and the fan starts up. Shuts down and LED #2 goes out. Then comes back on and the Fan gets louder and louder. Still no startup tone and LED's #3-5 never light . I tried hooking up a different working screen and no difference. I reset the SMC by touching the two test pads together and tested the button battery voltage which is okay. I find it hard to believe that the GPU on the logic board would have gone bad at the same time the screen fell off because there was no power to the unit. Wondering if when I attached the new screen with the old display cable, something may have shorted out the logic board. I do notice that the one of the pins on the display cable was bent so there could have been a short. Tried working cable and no difference. Any ideas?? I plan on hooking up an external monitor to see if the computer comes alive but if the GPU went bad after the accident that probably will not work. To say the least, I am thoroughly aggravated with OWC and will never make a purchase with them again. But I do not want to use this forum to bash so just rely focused on getting my MAC back up and running. Does it look like I need a new logic board?