Aporte original por: Chris Stables ,
You can start by ruling out parts. Put the logic board into a known good housing and screen. If you haven’t got a known good housing remove the logic board and connect a known good battery, screen and dock connector. If the problem still persists feel or put a bit of Isopropyl alcohol on the Wi-Fi chip and see if it is getting hot. If it is it may need replacing. If you have a tristar tester I would check hydra. It has a line under it that would cause a boot-loop and greyed out Wi-Fi. If Hydra and SWI lines are okay I would start taking some voltage measurements. The PP1V8_S2 and PP_VDD_MAIN lines would be where I would start since it is happening with greyed out Wi-Fi. Test the voltage while it is hanging on the apple logo. If diode and voltage readings are all right it could mean you have a communications problem from the NAND or CPU. I would check and make sure the IC2 resistors are okay especially where the water went and around the CPU. If it has sustained a decent drop it might pay to check for cracks in the coils around the CPU as well.