Chosen Solution
Hello everyone. I have am iphone X qualcomm that would not power. When i hook up only the top layer of the pcb to dcps, the top layer draws current before prompt to boot. But i tested with a DMM and found no shorts on PP_VDD_MAIN and PP_VDD_BOOST. now i wonder what other lines could draw current before prompt to boot. Any help is appreciated. THANKS.
How much current? It’s not like there is some main switch on the logic board that cuts all the current to the components. Take a look at the schematic and the moment a battery or a USB power source is connected, quite a few components receive VDD_MAIN. There is a line called PP1V8_ALWAYS and as the name suggests…it is always on. So if the board is still dead, focus on all of the subsystems powered by the PMIC to see if there are any shorts or related issues. They may be the cause of your problem.
Use this as a reference https://www.youtube.com/watch?v=nuZz_D1u…
