QuickTech

Doing this and not using an actual Apple hard drive will not turn out well in the end. A thermal sensor is needed to control the fan speed which I believe the fan is regulated if you have an actual apple HD. OWC sales the thermal sensors but they have none for the late 2012 - 21.5, the 27inch they do have it.

very good directions

I think I will NOT be trying to do this. To many potentials for something to go wrong beyond your control, even when being extra careful. I do not feel like replacing someone’s device if that happens.

it’s possible, I have the same issue. The #1 light is on when plugged in but soon as I press the power button it is gone….then no lights at all. Let it sit for 10 minutes plug it back in …no lights …nothing. I think maybe the power supply. I don’t think you can tell if it’s anything else like the logic board unless you have a known working power supply.