Chosen Solution
Power Button does not work to power on (or power off), my iMac 27"late 2012? Can I change/install a new Power Button? Where I can find it? Thanks! Jairo
While you have a 27" model the problem is the same as this one: Cable from power button broke during hard drive replacement. I would bring it into an Apple Store to have them fix it. It might be even an extended warranty repair (free) if you didn’t damage it in any way.
