Chosen Solution
So I purchased a 2010 Mac with a fried PSU it was black screening seconds after the boot logo came up. So now I replaced it with a new PSU and the black screening issue still happens but it takes longer to happen. I can use it for an hour or two but certain tasks make it wanna black screen but sometimes it doesn’t. Any help?
Either the dead PSU fried some components while it died when the previous owner had it (possibly CPU, GPU, Maybe some RAM.) or the PSU ruined the Logic Board or even the Display Controller (meaning new display replacment.) IMO Don’t ever buy a iMac with a dead PSU because it can kill/heavily damage at lot more than itself. EDIT: i would suggest to sell it for parts, keep the HDD and buy a iMac with a dead drive instead :)
