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| {{Repair Guide
| | The insides of the device removed from its housing. |
| |Device=IPhone 11
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| |Affects parts=Motherboard
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| |Type=Soldering
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| |Difficulty=3. Hard
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| }}
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| {{stub}}
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| == Problem description ==
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| <!--
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| Provide a concise description of the issue here. Be as specific as possible to help readers quickly determine whether or not this is the exact problem they are facing.
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| iPhone 11 not Powering on and pulls 2 amps or more from DCPSU before prompt to boot
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| [[File:Placeholder image.jpg|thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it!]]
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| == Solution ==
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| <!--
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| If the issue has a single, specific solution, provide it in this section and delete the sub-headers below. Otherwise, if there are multiple potential causes for the problem, outline the process of identifying the root cause and offer corresponding solutions below.
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| Do a full visual inspection of the board and check for water damage under the stickers on the back. Remove the foam around the connectors to get a better look at everything. You're looking for any signs of corrosion on or around components and ICs.
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| If there is no water damage, is is most likely a shorted capacitor on any of the below lines:
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| * '''PP_VDD_MAIN''' — This is the most likely line to be shorted
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| * '''PP_VDD_BOOST''' — This line is usually shorted when it's not VDD MAIN
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| * '''U_NFC -''' In some cases, the chip itself can crack & cause a short within the bottom board.
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| * '''Rigel (U4400)''' — This is a bit rare but it does happen
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| You'll need to inject voltage (4 V / 2 A) directly into the line you measured as short and use freeze spray (see here https://youtu.be/3MtLSQJvQxI) or thermal camera (see here: https://youtu.be/fkd4iDjgfvc) to spot the capacitor that is shorted.
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| In these cases, you can just remove the shorted capacitor and not replace it. The device will function normally with no negative effects.
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| Replacing it means you are adding more heat to the board to reinstall it, which increases the risk of something going wrong.
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| If you have a case of water damage, then you'll have to pay attention to the spots on the board where there's signs of water damage.
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| Often, you'll find corrosion on capacitors but also under ICs.
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| Since this is a 2 layer board, you can split the sandwich into 2 separate parts, top board & bottom board.
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| * Then you can check to see if the short is still present when connecting the top layer to the DC Power Supply by itself.
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| * If the short is still present, the culprit will be on the top board somewhere
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| * If the short clears, then the short is present on the bottom board.
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| ** So in this case, you can inject voltage into the bottom board to find the short.
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| '''Please Note:''' If you are using a DC power supply to inject voltage through the battery connector, like using an iPower Pro or DT880 (see here https://youtu.be/rawjB9yxe1A), be aware that Yangtze may heat up instantly. This is because the battery connector line PP_BATT_VCC connects to PP_VDD_MAIN through it, which creates lots of heat. In most cases, the short is not the chip itself, but a shorted cap. In rare cases, it's Yangtze itself. So try removing it & check if there's any shorts under Yangtze. If not, then the issue was Yangtze and you'll need to replace it.
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| ''Migrated from old wiki''
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