tcampbell34
Member
I have a 820-01041 that was liquid damaged and did not turn on. I fixed all of the damaged areas on the board and it now turns on and boots fine, but I am not able to setup touchID for some reason. Its not the normal error you get if the power button is not the original one, and there was some heavy liquid damage around the U4900/10/20 area (see photo from before I cleaned and replaced parts). I replaced all 3 of those and a bunch of the other components around that area, but I still get the same error. When trying to add a fingerprint, it will get to the point where it asks me to place my finger on the touchID button, and then as soon as I do, it gives me the error "Unable to complete Touch ID enrollment". Checking voltages with just the board on the desk with charger and another power button connected, I have PP1V8_MESA and PP3V3_MESA, but PP16V0_MESA is missing. It looks like U4900 creates that rail, but MESA_BOOST_EN is also missing. R4923 and R4954 are good. I'm confused on how this circuit works, so hoping someone can help figure out why I'm missing PP16V0_MESA and MESA_BOOST_EN