Hello Wise Ones,
I am working on an iPhone 12 that fell into a lake and has a short to the main power rail. I do a general look over the board and see no obvious physical issues such as burned-out caps or a split between the boards and the interposer. I separated the top board and the short seemed to disappear. I then checked every test point that I could and they are all not showing a short at all, even the spot where I initially tested. I assumed that something was causing a bridge in the interposer so I removed all the old solder, reapplied some new solder, and sandwiched the boards back together. The short reappeared! I then took it all apart again and retested all the test points and very thoroughly went through the pads on the interposer to see if I missed something and it all looked clean. Not sure what to do now, maybe someone has experience with something like this and can guide me to a repair? I will attach a screenshot of the area I initially tested to see if there was a short.
I am working on an iPhone 12 that fell into a lake and has a short to the main power rail. I do a general look over the board and see no obvious physical issues such as burned-out caps or a split between the boards and the interposer. I separated the top board and the short seemed to disappear. I then checked every test point that I could and they are all not showing a short at all, even the spot where I initially tested. I assumed that something was causing a bridge in the interposer so I removed all the old solder, reapplied some new solder, and sandwiched the boards back together. The short reappeared! I then took it all apart again and retested all the test points and very thoroughly went through the pads on the interposer to see if I missed something and it all looked clean. Not sure what to do now, maybe someone has experience with something like this and can guide me to a repair? I will attach a screenshot of the area I initially tested to see if there was a short.