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hello everybody! i had an iphone 6s for repair, it was discharging by doing nothing and found out that tristar chip was hot. i replaced tristar from iphone 7. now it is not booting, vcc_main shows the same as the battery voltage, charging takes max 0.1a. now nothing heats up after tristar change. pls help, is this short, or what? becouse nothing heating up.
It’s always better to do a bit of probing to try and understand where the actual issue is because every time you swap IC’s you are applying a lot of heat to the logic board and this can (and will) cause collateral issues. Unplug the battery and connect a known-good (preferably Apple original or MFi) charger to the phone. A properly working phone will show an Apple logo and boot loop. If the Tristar IC is bad then the phone will not do anything. This is not a definitive test but it will help in your troubleshooting. You should also consider that the Tristar replacement did not go perfectly or that you have power rail issues supplying Tristar. Finally, the actual charging circuit is the Tigris IC. Charge circuit failures can be difficult to troubleshoot because there are three IC’s (PMIC, Tristar & Tigris), the Battery and it’s SWI line as well as the charger and cables all interacting. You have to eliminate as many variables as you can and then focus on what’s left.
