Chosen Solution
Sometimes it will boot into the apple logo and loading bar. Will only power on with charger. Have tried to disconnect the battery.. while using the charger. The same problem. No water damage. What could It be? Logic board? Battery? Please help.
Disconnect the battery and mag-safe. Press and hold the power on button for 10 seconds. Reconnect the the battery and mag-safe. You should get a spontaneous reboot. It it does not boot all the way, tell us what it does do. UPDATE 9/25/18 At this point try booting up holding down the option key and see if it will see the repair partition. Next, I would try booting from an external source, both with the SSD blade in and out.
you can try this in the interim: boot into your MacBook Pro’s Recovery mode by holding down a Command key and the R key as it starts up. When the Mac OS X Utilities menu appears, select Disk Utility. On the left-hand side of the Disk Utility window, select your internal disk’s boot partition (typically called “Macintosh HD”). On the right-hand side, press the Verify Disk button if it’s not greyed out; if it is greyed out, or if it reports that it found errors, press the Repair Disk button. Once the verification/repair is completed, exit Disk Utility and select Restart from the Apple menu to restart into normal mode. Do you still get the same grey screen + progress bar + beach ball of doom? If it still not work than visit local authorized repair center.
Have you tried a SMC, NVRAM or PRAM reset? If so, try doing all of those types and see if it works out. https://www.macworld.com/article/2881177…
