27" 2012 iMac Not powering on after HDD change, Diag LED #2 flashes
Thought I’d help out a friend who had a 27” 2012 iMac with a failed HDD by replacing it. Changed loads of drives before on Windows machines so wasn’t too concerned about working on a Mac for the first time…… How wrong was I!
Cut the adhesive round the screen, got the drive changed, and use a can of air to clear some of the dust in the bottom vent holes and around the machine, didn’t touch anything else. The Mac now fails to power on, Diagnostic LED 1 stays on the entire time, LED 2 flashes every 5 or 6 seconds as it tries to power on, the optical sensor on the cheap USB mouse connected also flashes at the same time, this continues until you hold the power button for a few seconds to power it off. The fan does not spin, and there is no chime
Any ideas how to resolve this, or is it toast?