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

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No Service or very weak signal on iPhone 4s

Hi, I was trying to change the cellular antenna that I found out the blue coil and another piece is missing (as you can see in the picture, ignore the red and blue markings). I just want to know, what exactly there parts do and is there any way to bypass them. I have read about the blue coil but I do not know much about the other tiny piece beside it. Anybody knows what it does? please help me, its urgent.

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I tried to bridge the blue coil with a piece of wire (the other piece is still missing), the cellular antenna is back but when I trun on 3G it goes back to 1bar network. With 3G off it works just perfect but as soon as I turn 3G on the signal weakens. Any ideas?

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Sam, the components that are missing are the inductor L47_RF with the values of 5.6NH+/-0.2NH-470MA and the second component is the capacitor C14_RF values of 33PF 5% package 01005NP0-C0G 16V. It is part of the transceiver circuit, and looking at the schematic of the location of the capacitor, it is easily possible that this is what gives you your troubles. I would definitely replace it. Hope this helps, good luck.

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Thanks for your answer, I really appreciate it but do you have any idea, why the signal weakens when I turn on 3G. As I said, I bridged the two contacts for blue coil and signals are back (even EDGE works fine) but I do not get 3G or most of times only one bar.

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the capacitor C14_RF is parallel to the ant sel circuit. If it is not there, the circuit will be open and not get any signal etc.

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ok thanks, I've already ordered a blue coil an I know someone who can solder it for me but I could not find the other C14_RF thing, what will happen if I simply bypass it? I know it might seem weird but cellphone repair shop asks 100 to 130 Euros :( to get this thing fixed. Do you know how can I get it working without the C14_RF? I appreciate your advice.

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I am not sure where in Europe you are, but somebody surely carries the "C14_RF thing" which is a Murata GRM0225C1C330JD05D :-) I am hesitant to say to just try and bridge it with a circuit writer pen or similar, but I suppose at this time you do not have anything to lose

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I am having the same issue with my iphone 4s, the signals weakens as i turn on or off the 3g it works fine with celular data only but losses when connected to 3g...

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Sam will be eternally grateful.
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