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Apple's mainstream 2021 iPhone was released on September 24th and comes with a 6.1" OLED display, a dual 12 MP camera system, and in five available colors. Successor to the iPhone 12.

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Phone won’t turn on, high pitched small hissing sound when charging

Hello. I have an iPhone 13 that I bought. It doesn’t turn on, it doesn’t get recognised by laptop and doesn’t show any indication when charging, but the only thing it does when plugged into a charger is that I can hear very quiet high pitched hissing sound from inside the phone. When I first plug in the charger the sound is very small and it can be heard in ticks ( silence “tick” silence “tick”) like it’s trying to block electricity and over time the sound changes patterns and can be heard constantly. I also learned from the person I took the phone from is that when plugged into a charger for a while the phone gets hot. Might be a component in the motherboard that is getting hot when charged for a long period of time and I don’t want to repeat that because it might destroy the phone more. I want to learn repairing phones so Iam looking for answers of how to start troubleshooting. I suspect the fault being from the motherboard. I want to know how to get to the problem rather than just knowing what the problem is, though I would appreciate if anyone knows what the sound indicates. My question is, where and how do I start troubleshooting the motherboard.

Thanks in advance

Update (12/14/23)

Hello again, sorry for the late reply. Took some time for the majority of the tools to arrive. I plugged my probes into the battery connector and it shows a fluctuation in the amp draw. This only shows when I plug the phone into a charger. I don’t need to press any buttons, it just starts to draw when plugged into the charger. What does this tell me and what do I move on into now?

Edit: here’s a video https://streamable.com/mrxpbu

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If you want to start repairing phones the first action you would take in trouble shooting is to rule out a parts issue. The easiest way to do this is to install the logic board into a known good housing. If the problem still consists you can move onto the logic board. You will at least need a multimeter, power squid and board view software.

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Hello, thanks for the answer. I’ve seen videos where the motherboard and only a screen was used to power on the logic board. And ofcourse a source of power. I know from the previous owner that there are no problems with the housing or anything else and he thinks it’s a motherboard issue. If the screen was the problem then the phone would at least be recognised or vibrate when charged. I can’t think of components that would make the laptop not recognize the phone. Maybe charging socket only. But if that would be bad why do I hear the ticking noise from the middle of the phone? The board software can be sorted out and I think I have a multimeter aswell. Let’s say everything else is fine and we suspect it is a motherboard. How do we begin troubleshooting it? Thanks for your answer again

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@adnan44363 If the phone has a passcode it will not be recognised on a mac or PC until it is entered. This is what we call USB restriction. If you are sure it is a logic board issue you will need to start taking diode readings of the main power rails.

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Hello Chris thanks again for your answer. I don’t know about passcodes but I know it’s iCloud unlocked etc. About those power rails, I’ve heard about this before and I assume that this is the part where I need to pull up the board view software right?

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@adnan44363 You will need the schematics as well as the board view if you are not sure what power rails you need to check. Also these boards are layered so you might have to split them which will require heating platforms, re-ball stencils, microscope, soldering and hot air station.

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Hello again, sorry for the late reply. Took some time for the majority of the tools to arrive. I plugged my probes into the battery connector and it shows a fluctuation in the amp draw. This only shows when I plug the phone into a charger. I don’t need to press any buttons, it just starts to draw when plugged into the charger. What does this tell me and what do I move on into now?

Edit: here’s a video https://streamable.com/mrxpbu

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