When you replace the CPU or GPU or PCH, you need to rebuild the firmware and the PCH timing need to reset. Once you tried to boot up, the machine goes haywire because it doesn’t recognise the CPU. It got nothing to do with power supply or logic board.
There are very few people can build the firmware and according to Dan, Louis Rossmann may be able to rebuild it. I am not a celebrity so I only do the work for people who know me and trust me for what I do. If you are in California SF Bay Area, I can do it next day service but if you are from other part, you need to figure out a way to get it here.