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iPhone 8 Short?
I need some help figuring out where I should go from here.
When I connect the iPhone 8 (Qualcomm) the DC power supply immediately draws 1.2 amps or so at 4v.
But when I check there is no short on Main, Boost, or Battery.
With freeze spray U3100, U3700, and U5000 all get hot instantly according to some freeze spray.
I am not sure what U3100 does but U3700 is Camera PMIC and U5000 is small audio IC.
I removed U3100 just because I had seen problems there before (and it is the easiest to remove) but soon as I put another one on it
continues doing the same thing. (I know I know, never see hot remove hot). So I did diode mode underneath that chip and determined the 2 pads
for SYS_BOOST_LX and the 2 pads for VDD_MAIN were about half the values ZXW says they should be.
I don't know what this means or what I should look at. I know that L3100 connects
both those lines but its close to the CPU and that whole area is underfilled and I don't
want to play there willy nilly. What would you do? Visual inspection of the whole board was pristine
despite the phone being run over. L3100 looks perfect, also.
There are lines on the small audio ic that can mimic a vdd_main short or the chip itself could be shorted. I would suggest diode moding all of the capacitors around the small audio ic to see if you can find the shorted line or just remove the chip itself and check again.
That is a good piece of information to know. In this case, it turned out to be the Camera PMIC after all. I appreciate the response though it gave me encouragement to keep trying on it.