iMac Pro Teardown Highlights Modular RAM, CPU and SSD Along With Redesigned Internals - MacRumors
iMac Intel 27" EMC 2639 Reparatur - iFixit
21.5" iMac A1418 Late 2013 Disassembly SSD Hard Drive Upgrade Screen Replacement Repair - YouTube
2013 imac 21.5” power issue, replaced power supply twice, still no diagnostic LED on. The Mac will power on after being plugged in for several hours. And then powers on like nothing