MacBook Pro A1502 did not have backlight. It powered on and chimed when it’s booting but you can not see image on the screen. With the help of flashlight, you can barely see dark icons on the screen. Because it works in a kind of normal way, most circuit of the motherboard should work fine, the issue must be related to backlight circuits. Here’s the clip when I was repairing it. I finally found there’s a big capacitor of the LCD backlight out (High voltage) is damaged and shorted to ground. After removing it, the backlight came back.
