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苹果 iPhone 5s 于2013年9月10日公布。该设备的维修与以前的型号相似,需要螺丝刀和撬棒。可使用GSM或CDMA / 16、32或64 GB。颜色有银色、金色和太空灰。

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No Imei / Modem Firmware

So what happened is that we cleaned the little components and the front display connectors located at the top right of the logic board as there was some slight liquid damage causing the touch screen to behave erratically intermittently.

This in result solved that issue as we tried multiple new screens before that presented the same issue.

Now after doing that the imei and modem firmware is missing. Modem firmware says nothing and the entry for imei in settings about phone is not even there. I was expecting it to say imei with nothing at least.

Now the problem is that I don't know what capacitors or inductors to check on the logic board that connect to the baseband chip to power it. I doubt the baseband chip itself has gone bad. Dataline for baseband chip is probably fine too.

Any boardview files or schematics to look at to diagnose this issue better?

I have a feeling one of the capacitors or inductors blown up from a short somehow.

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@benjamen50 contact me by email for the documents you need.

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I managed to fix the issue by taking off the metal shields for the board at 450°C.

It's like reheating the board fixed the issue so problem solved. Weird..

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The baseband flash chip is the chip covered in underfill next to the display connectors.

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Oh, that explains why it decided to not work after cleaning the upper part of the board with 99% isopropyl alcohol. Needed more cleaning. Anyway fixed now as said above.

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Then the best solution for you is to flux , solder , replace the capacitor (most common enemy each time) ,with a new one to be sure.

Take a multimeter and test it out

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Ben 将永远感激不已
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