Chosen Solution
I recently fixed this iMac with a new SSD, installed Linux and everything was fine.Suddenly it just doesn’t start anymore.Fan is spinning, motherboard led is on, but that’s about it, nothing else happen.I was able to get it on once after this behaviour, by just unplugging cables and plugging them back. But no more since.I’ve tried SMC, NPRAM reset.When I remove the RAM and turn it on, I’ve the “hardware beep” indicating hardware issue. When I put it back on, its back to the same issueI take this as a good sign. It doesn’t feel as anything is broken really.but I’m short of ideas on how to proceed further and try identifying what’s wrong. Any tips? Update (01/19/2022) Well, as I was about to try T key, the iMac chimed and displayed a white screen that seemed to last forever.After trying OPTION key and PRAM reset, to no avail, I tried SMC reset by just unplugging the power cord.After trying PRAM reset again, I just got the linux installed OS to boot, after a quite long time thougfh, like 20-30s. But NO PRAM.I’m not sure what’s going on but the entire thing is highly unstable. No sure what this is indicative of. Some dying hardware?
Hold down the option key when started to try and get internet recovery up, it may be having issues with the software has it had linux installed.
I would give this a try as unlike other actions tis one is strictly EFI (BIOS) based so the OS your system is running won’t effect it. Restart your system with the RAM installed and press the T key which is the startup option to enable Target Disk Mode, you should see a Thunderbolt icon dancing about on the screen. Do you? Reference: Mac startup key combinations
