Chosen Solution
Hi My phone suddenly dead. It goes black screen with led and when trying to reboot with home+power it will not boot. Checked with power supply current draw only below 0.1 A. Checked: Pp bat line on tigris shows 3.9 v Pp1v8 sdram got 1.79v Pp1v2 sdram got 1.12v Pp cpu got 0.80v Changed tristar and phone was booting all working fine but only last for 30 minute until dead again. Remove tristar got short on pp1v8 sdram. Try to remove caps pp1v8 sdram near to tristar short still there. Then i remove tigris. Short still there on pp1v8 sdram. I try to inject current to that line with 0.8v but miracle happens. Short on pp1v8 sdram is gone. Reball back tigris and change new tristar. The phone does boot. All working perfectly no heat no battery drain. Able to use for 5 hours until it died again with no respons on power and home button. Previous work on this iphone meson changed with m1 jumper. Nand reprogramed to change sale region and apple boot color. Baseband cpu reball with two jumper due no imei and baseband firmware. Those work done disember last year. Im still thinking what cause of this. Needs help. Thanks. Update (04/12/2018) Phone now booted. Reball pmic. 6 hours till now still working. Ordered new pmic in case failed again.
I have two concerns here, the first being that you have an occasional short on PP1V8_SDRAM and the second that this logic board has been through a lot of surgery. Those two things could be somewhat related or not. So after the phone worked for 5 hours and died, was there any shorts on PP1V8 or did you find something else wrong with the device. You should check all of the outputs fro the PMIC to see if any other lines are shorted and that may give you a clue as to what is wrong with the device.
