Fifth generation of iPhone. Repair of this device is straightforward, and requires screwdrivers, prying tools, and patience. GSM/CDMA / 16, 32, or 64 GB / Black or White.

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replaced cellular antenna but the reception is still bad?

The phone was dropped, back glass was broken and the reception was made worse afterwards. After I replaced the back glass and cellular antenna the phone will get 1-2 bars when it should be getting 4-5, then sometimes it will get no service. What else in the iPhone 4S affects the cellular signal?

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just check that this part is connected properly iPhone 4 Cellular Antenna (GSM/AT&T) it controls reception. check also that the metal prongs are under the metal shield and all parts in the guide highlighted as needing to be cleaned and free of grease (ie the dock connector flex) are actually clean and well connected.

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In reply to pollytintop, I replaced the entire speaker and antenna assembly. What parts of the dock connector do I clean and what do I clean it with?

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did we checked that the cellular antenna cable socket on the logic board is fine. Could be be because of being dropped it has been broken and not connected to logic board properly.

The cellular antenna socket is near the battery connector.

Do check the connectivity for the socket on the logic board.

If you think i answered your question please rate (score) and mark it accepted. :)

Thanks

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It looks fine, maybe it needs to be cleaned? If so, what with?

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you can clean it with isopropyl alcohol or a cleaning agent, i am sure we would be having that here as a part of repair kit.

Also now that i can the pic posted by you you can refer my answer below :) thanks hope it helps

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The back cover itself does have an impact on reception, as it acts as a ground plane for the motherboard. I have seen iPhone 4's and 4S' alike with serious reception issues simply from not having a good back cover properly installed. It is not common, most of the time the phone should work normally with no back cover on it whatsoever, but I just wanted to mention that it is a possibility.

Also if you have access to a microscope and multimeter, check continuity of the inductors (small rectangular 2-pin component that is essential a piece of plastic wrapped in wire) near the antenna connector. If one were knocked loose due to impact, it will also cause this issue.

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I've seen back covers that have some sort of metal area so that the grounding clip by the battery can come into contact with it, but for this phone neither the old or new back glass/cover had it. I tried the phone with no back cover but it makes no difference. I don't have access to a microscope though I've got a multimeter, so what am I checking and what should it be if it is working correctly?

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Maybe the washer in the corner of the speaker assy is missing. It connects the sleeker to the bottom ring as an antenna.

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Was bought second hand, took out the logic board for further inspection, this is what I found

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Man that is a mess, unless you have some serious skills and tools, you won't be able to fix that on your own. I have done repair jobs like this before and typically you need a fine-point soldering iron and/or heat gun to replace these components properly. A microscope is basically a necessity for this type of work. Also I don't know off the top of my head what components used to be there, so I would find a bad motherboard from a water damaged phone or something and steal parts and put them in exactly the same place. There are definitely missing pieces there - Most likely they are inductors for antenna tuning, and inductors are coild of wire with near-zero resistance that provide a specific impedance based on frequency. It shows 0 Ohms on your meter, but at 1900 MHz it's much higher than that, so making a short-circuit often won't help your situation.

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From the pic can see that a inductor and a Capacitor is missing on your PCB.

I have attached a pic showing the components missing which are circled in green.

I have also given a solution which you can try, you have to solder a wire same as shown in blue color in my pic see it that works . . . . you can keep us posted.

If that dosent works probably you to solder those to components shown in green circle in my pic.

If you think i answered your question please rate (score) and mark it accepted. :)

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Man, based on electronics fundamentals, you are making a jumper to bypass an inductor AND a capacitor, I seriously doubt this will work properly, it will severely affect the impedance and possibly make it worse. Personally, I think the best option is to replace the components with identical components. Buy a smashed up iPhone and jack the parts from the motherboard, and that will work for sure, I guarantee that. If you knew the exact component values, you could purchase these pieces individually on Digikey.ca for about 12 cents/piece, and pay 8$ shipping Canada wide.

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Dan i have tried that and it worked for me in iphone4 and

its a solution suggested in few more websites

Links provide below :-

http://bdsolution24.blogspot.in/2013/01/...

this is for iphone 4 but the circuit it pretty much the same

http://www.forum.shaarpmind.com/showthre...*-its-kepping-searching-and-no-service-only!-Apple-iphone-problem

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I see your logic based on the PCB traces that you are jumping, and I'm sure it could work but I would expect a lack of performance, slightly less reception than the iPhone was designed for. If you bypass a tuning capacitor and inductor like that, the antenna will no longer have 50 Ohms impedance as seen by the IC in your picture at the design frequency, and sensitivity will most likely decrease significantly, so where you would normally have 4 bars reception, you may only get 3 or 2. It would at least get the phone up and running again though, personally I would advise going for 100% repairs and put it back the way it's supposed to be if you have the resources.

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Hello,

I have an iPhone 4s also with reception problems(1-2bars MAX), after taking the cover of, i noticed

the white component was completely loose (the one circled in purple on the attached picture, sorry to Varun Gargi for borrowing your pic, hope you dont mind)

picture: http://13o.imghost.us/Qy/kqF2SVK2dQ3uCpa...

anybody have a clue what this component is? or if it could be simply bypassed?

cheers

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Not worth troubleshooting at the component level. You can get a motherboard for a 4S off ebay for $6

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