Chosen Solution
i have an ipad air that came in not charging. it pulls .09a when powered off and when its booted pulls 0… charge port looks fine and when i plugged it in with battery disconnected it showed no apple logo. so i replaced tristar once with the exact replacement 1610a1 then it looped and got red screen. so i took that tristar off and decided to replace it with the updated model 1610a3. now it dosent have the red screen anymore and boots to the lockscreen again. but still wont charge…only pulling that same .09a. then i touched up the solder connections on the charge port and no change. tried with the original battery as well as a replacement. still cant get this thing to charge. another thing i should add is this came to me for not charging after another shop attempted to replace the glass. but i was the 1st one to remove any shields or take the board out of the housing.
The iPad Air can be a pain to diagnose. Start by doing a full continuity test on the charge port, not just inspecting it visually. If that is good, then a fresh battery & Tristar would be the next steps (which you have already done). After that, check the rest of the charge circuit (MOSFET, Coils etc). After that, you pretty much only have the PMIC left…
