Chosen Solution
Hi all , , i’ve got an iphone 6s here which i was told had been water damaged , having taken it apart it has obviously had a repair attempted already as the shields were off and under fill dug away , the board looks relatively clean with no signs of corrosion there are however some components missing , i think whoever took the under fill off was a bit heavy handed , as FL3202-1 was missing , i believe this is a filter on the vcc main to camera .. am i right in thinking the phone should still boot without this ? The phone will not boot nor is it seen by itunes I have checked voltages around tristar , PP_VCC_MAIN is present, so is PP3V0_TRISTAR . and PP1V8 and PP5V0_USB , I replaced tristar to rule it out , still no change My bench ps reads 15 ma draw which changes to 27 Ma when prompted to boot .. charger current reads 43 ma . Nothing seemed to be getting warm on the board so i started checking randomly for shorted components , i found line PP_1V0_SMPS3 is shorted to ground , from what i can see there are only 3 components on this line and points under U_BB_RF , should i inject 1 v from my ps into this line to see what gets hot ?
The phone should boot with the missing filter. As for the short, there is also a bank of 8 caps to filter this line, check page 40 of the schematics. I would also check the other outputs of the U_PMU_RF (the RF version of the PMIC). The short could cause the PMU_RF into current limiting and then causing other issues with BB and the rest of the RF circuits. That might be why the phone does not boot. It appears there is more damage than what you would expect based on the visuals. I would probe the PMIC and PMU_RF to see if there is anything else. You could also inject voltage.
I see the question marked answered, but the outcome of the issue is not explained? Did you manage to get the phone to boot OP? I have the same issue
