Chosen Solution
I have a motherboard here that was used in the store as a tester for screens Now the motherboard has gone bad When turned on, it gives a brief apple logo in the beginning and the screen turns black with a working back light. So after testing out the voltages, this is what I got. FL2027 = 1.8v. PP1v8 FL2061 = 0v. PN5v7 FL2037 = 0v. PP5v7 FL2035 = 1.8v. LCM enable FL2036 = 0v. LCM reset FL2050 = 1.64v. PMU photon I replaced the chestnut and while replacing it the coil (L1519) got chipped so replaced that one as well. Now the backlight doesn’t turn on anymore. What could be the problem?
The PMU_Photon line seems a little low. It is pulled up (R1301) to the 1V8 rail and in essence, it shouldn’t really be pulling any current. I wonder if you don’t have an issue with the PMIC. You should check the voltages it produces to see if the problem is coming from the PMIC.
