I have a Macbook Pro, model A1502. While watching videos, the screen just cut to black. Now it won't do anything on boot - the MacBook screen just comes up black. I've tried zapping the PRAM, (ahem, NVRAM), an SMC reset, nada. It seems that the backlight is working - it's "LCD black" black, meaning it's not truly dark it looks like the backlight is working.
Safe boot, boot to recovery, verbose safe boot, nothing happens.
I have an external monitor. On the external, it shows the apple boot screen, the progress bar gets to about 40% across, then even the external monitor goes black.
My guess is, hardware issue, Genius Bar time? I hope not... don't feel like buying a new board.
EDIT: it needed an SMC reset. I didn't do it properly, and it did work, eventually.
EDIT2: 1) you don't want a full battery for an SMC reset. I always had it charging. I unplugged from power and plugged in some spinning-rust hard drives to sap power. This helped. 2) I found mirror mode. Command F1 mirrors the main login screen to the external monitor. I can then login do a backup and wipe the drives