Chosen Solution
So my son says he was using his laptop and out of a sudden was prompted to restart/shut down/etc. Eventually the computer shut down on its own and since then has not passed from the apple progress power up screen. Please refer to this video: This embed seems invalid. Please check the URL. Already tried with no success or change in behaviour: Swapping the hard drive with that from another working MBPSwapping RAM modules with those from another working MBPReseting PRAM and SMCStarting up in Safe Mode In all case, I’m always getting the same behaviour. I believe the issue may be shorted power button (also, considering my son says the problem began when he was randomly prompted to shut down the computer. That said, what I find odd is that the computer completed the onboard diagnostic utility without shutting down and it responds when pressing the power button to turn it on. Thank you again for your input. Update (10/18/2016) UPDATE: My son just “confessed”… there was a part of the story that was missing… he says he was cleaning the keyboard with a Windex-like product and did a squirt or two directly on the keyboard when the problem began. At this point I’m wondering if replacing the keyboard would fix the issue; I know the power button is connected to it. I’m also wondering if there is an issue with the logic board (but again, booting directly to the diagnostics utility COMMAND + D yielded no hardware errors). I notice that upon booting the computer fan runs at full speed and am also noticing that the magsafe power cable led is always in “green” (never in “orange”). Don’t know if these are telling sign of possible logic board damage. Thanks again for your input.
To isolate out the keyboard & trackpad out you’ll need a USB keyboard & mouse. Follow this IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 Logic Board Replacement just doing Steps 1 & 2. Then carefully disconnect the keyboard/trackpad ribbon cable jumping down to Step 11. Now place the system on it side so you can still plug in the MagSafe, keyboard & mouse. You’ll need access to the bottom as you’ll now use a jumper to short across the power pads. Here’s a figure to help you finding them.
See if the system stays running then. If it does you’ll need to try to dry out the keyboard to see if that fixes things. I would put it on a sunny window sill so it gets warm (not hot).
