Can someone explain how to test a PCB for short circuit?

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iPhone 5s

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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Josh White @joshwhite70874

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Flash Technologies

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发帖于: 2015年7月23日

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Can someone explain how to test a PCB for short circuit?

Hello again ifixit,

Trying to begin repairing some water damaged/ no power phones here. iPhone 5/5c/5s. Can anyone point me in the right direction of diagnostics for a water damaged board? I'm really not sure how to find a short, or an open trace as I have no idea where on the board to measure voltages. Are there schematics out there that show all the correct voltages? I have not been able to find any.

I guess the first part I want to know is, should there be continuity between the battery terminals on an iPhone 5/5c/5s board? I've seen people talking about that as a way to find if you board is shorted, is there any value to this? I also read about hooking up an external power source(low voltage, high current) and then replacing whichever components start overheating.

I guess I just need to know where to go to start making sense of these units with no signs of life. Its a mess at the moment. Thanks in advance

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hi. i have all the schematics for the iphones and ipads. let me know the one you want and i'll mail it to you.

由 trevor 完成的 2015年7月27日

What, really?! That would be awesome! I'm really looking for iPhone 5/5c/5s schematics. iPad 3/4 would also be very cool.

由 Josh White 完成的 2015年7月28日

can you give me your email address so. will mail them to you

由 trevor 完成的 2015年7月28日

joshuadavid1993@gmail.com

I really appreciate it

由 Josh White 完成的 2015年7月28日

I've got the same problem I ask for help

and my email smsm6666666@yahoo.com

由 smsm6666666 完成的 2015年8月3日

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Jason Gan @jasongan35847

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Dorm Geeks

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发帖于: 2015年7月25日

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Short circuits produce heat, so feel for heat.

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I'm really wondering how to test for a short with a multimeter, some of the components are so small that its hard to find where the heat is coming from

由 Josh White 完成的 2015年7月27日

Not practical. You have to test them individually out of the circuit, which means desoldering everything you see on the board.

由 Jason Gan 完成的 2015年7月28日

I see. For some reason I did not realize I need to take them out of the circuit. One other small question, I have a ton of iPhone 5's that seem to have a serious short right above the sim card area. They get burning hot, but I can't single out the component. It seems like a common issue. Any ideas?

由 Josh White 完成的 2015年7月28日

Could be the CPU, U2, or a million other things. I can't tell you without seeing it.

由 Jason Gan 完成的 2015年7月29日

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hi. i have all the schematics for the iphones and ipads. let me know the one you want and i'll mail it to you. — trevor
What, really?! That would be awesome! I'm really looking for iPhone 5/5c/5s schematics. iPad 3/4 would also be very cool. — Josh White
can you give me your email address so. will mail them to you — trevor
I've got the same problem I ask for help

and my email smsm6666666@yahoo.com — smsm6666666
I'm really wondering how to test for a short with a multimeter, some of the components are so small that its hard to find where the heat is coming from — Josh White
Not practical. You have to test them individually out of the circuit, which means desoldering everything you see on the board. — Jason Gan
I see. For some reason I did not realize I need to take them out of the circuit. One other small question, I have a ton of iPhone 5's that seem to have a serious short right above the sim card area. They get burning hot, but I can't single out the component. It seems like a common issue. Any ideas? — Josh White
Could be the CPU, U2, or a million other things. I can't tell you without seeing it. — Jason Gan

iPhone 5s

Can someone explain how to test a PCB for short circuit?

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