Epoxy over SMDs on iPhone 8 logic board?
Here's a stitched image of the area just to the north of the battery connector on my mainboard. (The phone's on the bench turned sideways with the charge port to the right. Click on the image to get a better view. Sorry for the poor contrast. Black components, foam and goo on a nearly black board. The only thing that really stands out are the gold contacts.)
My iP8 mainboard developed charge control problems after replacing the charging port assembly. I was running thru the list of causes of charging problems, first looking to see if I had accidentally knocked off one of the SMDs near the battery connector with an errant fingernail.
When I got in there with a microscope I was surprised by what I found. You can see the edge of the battery connector at the bottom of the photo and a mosfet at the top slightly to the right of center. In between that mosfet and the test point at the center of the image, there should be another mosfet package, one that is often knocked loose by accident. But on my board there's this weird black crud covering the area and extending horizontally, covering many other smaller SMDs near the connector as well.
In the image it looks like goo, but in fact it's a very hard substance, like ceramic or epoxy. I assume this was done during manufacturing to prevent accidental damage when connectors are being mated/unmated. Has anyone encountered this before? I haven't seen anyone else mention it on this forum or on other phone repair sites. I'm hoping someone can confirm my guess -- that the second mosfet and other SMDs are there under a layer of epoxy -- or give a alternate explanation. Thanks!
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