Aporte original por: Minho ,
Have you checked the voltage generated by the PMIC (U8100)? It should be 20.4V . Even if the diode and filter are okay, that doesn't mean there is any voltage going to to the backlight. If there is no voltage, it could be the PMIC or the coil (!) that is the problem. Download the schematic and search for PPLED to follow the circuit to know where to probe.