Hi, I am currently repairing a imac a1419 that chimes however nothing is shown on the large display.Plugged it to an external monitor and it does show the flashing folder. It seems that the units backlight has been effected. I am familiar with replacing the fuses and LED driver on the macbook however I can't find the fuse for the LED driver. I located the LED driver HV9989 on the logic board and have taken a few pictures if anyone can help me locate it. Apple part number for the logic board is 820-3478-A.