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Repair information and guides for the fifth generation of iPhone. Model: A1387

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What is work of U18_RF in iPhone 4s?

I want to know that what is work of Baseband Power Diode U18_RF in iphone 4s?

Answer this question I have this problem too

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Jay, you want to know how to replace the IC?

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No but I also want to know replacing idea.When I heat the ic upper part broke and internal material still jointed with pcb.How could I completely remove ic from pcb.and please also provide main work of this ic in iphone 4s.

One thing more: From where can I buy U3_RF for 4s?

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Hang on, you tried to reflow and overheated the IC? It melted on the board? Post images of this with your question. That way we can see what you see

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Oh I can understand about image but not possible now ,because i'm out of town.I think ic not properly melting,any liquid or paste required for easily removing?

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Jay, have you done a reball before?

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2 Answers

Most Helpful Answer

Take it off with some flux and an iron. U18_RF is some sort of baseband logic gate. If it is gone, the phone will always be searching, it is one of the common 4S battery pry damage faults that will result in a phone always searching and not producing an IMEI.

You need to replace it.

Try to avoid using hot air on tiny phone boards if possible. The likelihood of doing more harm than good is too high. It is not necessary to use any hot air to remove and replace this component.

jessa

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1 Comment:

Thanks for very useful response.

How do i confirm about this ic is this working or bad.

My iphone not searching. . but No service problem.

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this ic change to restored error 48 and all error problem solved

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