Chosen Solution
Hello, Firstly: this is my first post on the forum so bear with me please, and i am sorry if this question has been asked before. I have an iPhone 6 that does not work. I have tried new battery, connecting battery terminals to a lab bench supply, connecting to a computer and charger. Nothing seems to work. When connected to the supply it draws 1.4 amps, then about 0.5a and then 0, and this cycle repeats. First i thought this could’ve been bad tristar, but since it also doesn’t work on bench supply i am not sure of that anymore. I have also tried removing the battery protection circuit and connecting the power supply to the battery contacts, but then I measure 3.7v between the iphone ground and the supply ground somehow. I am sure i connected them the proper way around tho Does anyone know what else i can try? Thanks in advance!
When dealing with a “dead phone”, you really should do some investigation before swapping out parts. While many times a Tristar replacement will work, when it doesn’t, you now have a board that was heated and that entails lots of variables. It’s like going to the doctor and saying you have abdominal pain and nothing else. It could be caused by so many things, some serious, some not. The doctor will ask you questions, probe you and take vitals. They will talk about family history etc. Ask the customer how and when it failed…do they use cheap chargers? Look for signs of physical or water damage - don’t always trust what the customer says. Probe the main voltage rails at first before applying power and when that looks good, start probing the PMIC outputs and all major subsystems (Tristar, Chestnut, Backlight, Mesa etc that could cause upstream effects. Usually you will see some clues that help you identify the cause.
