Hello everyone, I need some help before with the backlight repair on a macbook pro a1278 mid 2012. It does turn on everything works except the backlight. My dilema is if I replace the hole lcd unit and the problem persists. I want to eliminate possible causes before I go and replace the whole screen. Can somebody guide me what steps to do first and where the parts are located to troubleshoot? (backlight fuse, etc) Thank you in advance.