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Apple выпустила смартфон 4 ноября 2017 года в двух различных конфигурациях: A1865, A1901 и дала название iPhone X. Доступны варианты с разными стандартами мобильной связи: GSM или CDMA; с двумя объемами хранилища: 64 или 256 Гб; двумя различными оттенками корпуса: серебристый и Space Gray.

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iPhone X won't activate, baseband problem, probably CPU short!

Hello, I’ve a problem with iPhone X. I have bought it light water damaged with boot loop. I have done that repair many times, it was caused by water damage on ambient light sensor of top speaker. After disconnecting this flex of top speaker, iPhone booted up normally. It had been logged into some guy’s account, so he cleaned the phone using Find my iPhone (worth to notice that it was logged into iCloud account but kept asking for password, just like it wasn’t confirmed). He cleaned the phone wirelessly and the white Hello screen showed up. I started logging in, but after connecting it to wifi there were warning sign screen showing, that iPhone cannot be activated. I had teared it down (motherboard and phone interior had no water damage signs), desoldered double stacked motherboard and started looking for baseband problem. I have checked every single pin, capacitor and resistor of baseband with no problem. After that I checked baseband PMU, even had desoldered it to check short lines, but found none of them. So there is no problem with baseband. I thought that it might be caused by not properly soldered pins between 2 boards of motherboard so I tried to solder it. As I had no stencil for recalling, I failed (phone was booting normally but I had no touch screen). At second desoldering, few pads of upper layer felt off. Then I checked them, and found out that pin : AOP_TO_WLAN_CONTEXT_B (fifth from left, closest to center, under u2700), is shorted to GND. I checked pins around and every single one shows around 0,420v. This fifth pin is not visibly shorted with any other pin. As it is connected directly to CPU, I think that it might be problem related to shorted soldering pins of CPU (as this is pin AW8, close to ground which is AY7 and AY9). I can also add, that phone is booting up normally with half of motherboard. So long story short:


-Could anyone measure in diode mode, value of fifth pin related to GND (posted the picture under)

-If CPU is shorted, could it be problem why my phone doesn’t want to activate (because as said baseband circuit is fine, unfortunately I hadn’t checked SIM card before disassembly).


Thanks for help

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Ответ на этот вопрос У меня та же проблема

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The value is OL

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@imicrosoldering so it’s shorted. Could it cause the activation problem, because it’s WLAN line

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You would need to compare it with another board. ZXW displays OL but I think it should be around 0.4 If it is shorted it could be causing your problem.

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@imicrosoldering Ok, could it be shorted somewhere close to lines, or could it be shorted under the CPU ? Desoldering CPU is the last thing I want to do, but I have been cleaning pad few times and found no problem close to that pin .

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its most likely a nad/cpu short

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hello Jakub,

firstly, you have got a short - clean s93 pad - there is short to ground I see it on your picture (not under cpu).

secondly, Wlan_content_b has’t effect on BB_CPU and it’s completely different sub_system.

Finally question: was there “info - your iPhone can’t be activated” or “worning - your iPhone can’t be activated”? Both two are quite different and they do not apply to the same.

So I think that, you started badly right from the beginning and as a result of that, you broke a sandwich yourself.

My s93 pin has 0,380.

I have rhetoric question: what heat did you use, 320, 350 or more? Interposer was designed for 140-150 Celsius on upper side. Make your own conclusions about it.

My advice:

  • clean all pads on both parts (be carefully - there are few spacers - don't lose them
  • don’t learn form YouTube - try read some books about re-work electronics - there’s lots of. (practice all the time, every day. But not on customers boards. Buy on eBay locked ones and learn yourself)
  • use x/XS bracket like iSocket or some similar one and assembly it in one piece. Use dock flex and screen panel. Connect DCPS and prompt to boot by tweezers. I think, touch will back.
  • connect lighting and use 3ut. Find position: baseband ver, firmware ver and build no. - if you can find that three, it’s mean your baseband woks (in that regard) . When you learned enough in text few months a lot, you will use a low level AT-command like: connect/baseband —autotest (command to control/test baseband functionality)

regards, I think its all.

PS, comments above, shut it all to the bin, all’s rubbish and bullshit.

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