820-3481 A1419 iMac No Backlight

[thetech]

Late 2013 27" iMac. No backlight, definitely has image on LCD. Checked pins 1-4, 2-5 and 3-6 on BKL connector, no voltage at all. Can't find a schematic for this board anywhere. Replaced LCD cable and reset PRAM, no change. Grateful for any help on this.

 

[dukefawks]

Yeah this is gonna suck. You are pretty much on your own figuring this out. There is a backlight fuse on the board. Check for shorts to GND on all LED lines first.
You should first make 100% sure it is a board problem, find a cracked test LCD.