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Slightly bent logic board - sporadic WiFi and Bluetooth

I dropped my iPhone 7 matte black and the housing bent a little near the top of the phone. I replaced the housing along with the screen, and as I was taking out the logic board I noticed it was slightly bent at the top. A corner of the metal shield unbuckled from the motherboard, but I didn't see any cracks in the board. Whenever I go to turn on WiFi or Bluetooth, it would freeze up and I'd have to force a reset. The settings icon would grey out as I press it and my apps wouldn't want to open.

Also, is the WiFi and Bluetooth both combined into one chip? There is a silver chip at the top of the logic board which seems to be responsible for both radios. Could it be possible the bend caused a solder ball to crack and loose connection? Would a reflow and some flux reconnect the chip?

Thanks

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Posted: Oct 2, 2017

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That's exactly the same conclusion I came to as I was reading your question. Don't reflow as that can have unexpected consequences, especially on underfilled IC's. The heat causes the solder balls to expand and that causes pressure under the IC. When they are locked in with underfill, the pressure builds to the point where the solder balls have no where left to expand and they "POP" out from under the IC. That causes all kinds of bridges, shorts and poorly connected balls.

The proper thing to do is a full reball. However, in your case, it is quite possible that some traces may have been damaged as well.

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iPhone 7

Slightly bent logic board - sporadic WiFi and Bluetooth

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