iPhone 4 No reception after screen replacement

Discussion in 'iPhone Tips, Help and Troubleshooting' started by LuMe96, Jul 5, 2011.

  1. LuMe96 macrumors newbie

    Jun 8, 2011
    Hi all,

    I would need the help of an expert here.

    A friend of mine broke his iPhone 4 screen. He got a new Screen assembly and did the replacement by himself. Everything works fine, except GSM reception so he asked me to have a look.

    I completely disassembled the phone twice but couldn't find any obvious reason to that pb.

    - WiFi / WLAN / Bluetooth is fine
    - all hardware buttons work fine.
    - Screen and Touch are ok
    - GPS is ok

    The only thing not working is GSM reception. Outside I sometimes do get a very weak signal where my own phone is on full strength but most of the time I just get Network unavailable. Looks like an antenna issue, but I really don't know what / where to check :
    - the antenna cable coming from the Speaker/Dock connector Assembly is connected to the logic board
    - The little gold plated metal strip at the top of the logic board is in touch with the iPhone housing
    - The two connectors/metal strips below the Speaker assembly look good as well.
    - The speaker assembly is in place and fixed with the corresponding
    - The little metal strip on top of the battery connector is fine as well and should be in contact with the backplate.

    Not having found any info on the GSM antenna, could someone please point me to the right direction (where / what else to check)?

    Thanks for your help.

  2. g12007 macrumors newbie

    Jul 13, 2011
    i have the SAME problem...
    i have pretty much done everything you have done but still no signal.
    i put my sim in and it says searching and then no service over n over..

    anyone have any ideas about this problem yet ? :confused:
  3. LuMe96 thread starter macrumors newbie

    Jun 8, 2011

    I can't really help you out, but I did some further research and did locate the GSM antenna.

    Part of the metal housing is used for the reception. The connections to the housing are the following (I included the Steps where you'll see the parts I talk about, refer to this iFixit guide) :

    - the contact clip (Step 5) making a connection with the backplate.

    - the little gold-plated metal strip on the top of the logic board (right next to the screen / LCD connector (Step 13, on the left of the 4.8mm (green labeled) Phillips screw).

    - with the iPhone backplate off and LCD face down, the screw in the bottom right, the one holding the speaker/mic/dock connector assembly (Step 20)

    - the main part however is the little cable + connector scotched onto the speaker/mic/dock connector assembly at the bottom. (Step 11).
    Make sure that the connector is firmly connected to the logic board. You'll read all over the net that this is the WiFi antenna, but that is WRONG. I've tested it on my working iPhone and WiFi is working fine with or without that wire connected to the logic board. However, as soon as you disconnect that wire, GSM reception drops down to "No service".

    In my case all those points were fine but still no service. I did however get to repair a second iPhone 4 with no service and in that case, the Step 11 connector was not firmly connected to the logic board. Afterwards, reception was fine.

    Hope this helps.
  4. g12007 macrumors newbie

    Jul 13, 2011
    i have the same problem after a lcd screen replacement..
    i changed the speaker housing with the so called "wifi antenna" and still
    no signal :mad:
  5. g12007 macrumors newbie

    Jul 13, 2011
    did you ever find out how to fix this problem and restore the signal on the 1st device where all of the points were fine ?? :confused:
  6. SSmoked macrumors newbie

    Jul 12, 2010
    Ditto. Having the same issue and checked everything. I ordered a new screw set and am going to take apart/clean and install new screws and antenna flex cable. Hopefully that's it...
  7. sam12345-2008 macrumors member

    Jan 6, 2011
    Sussex, UK
    Having a similar problem at the moment, but mine is with the WiFi.
    Also the rear camera just stopped working after i switched camera to the front view.

    A nightmare... Probably have to replace the wifi antenna and the rear camera just to rule out hardware issues.
  8. chomby1991 macrumors member

    Jul 3, 2008
    Australia ->queensland ->Rockhampton
    Ive just had this issue, I replaced the screen and my reception dropped to no service. In ifixit, it explains in one of the steps to make sure you didn't lose the little blue inductor to the bottom left of the aerial cable. In my case this was missing. With the back off the phone i used a flat bladed screw driver to bridge the gap between the 2 solder points where the inductor was and this brought back signal immediately hence proving that this was in fact the problem, We used a bit of solder and a steady hand to join the gap and it now works perfectly fine again. The quality of phone calls seems to be the same if not better.

    During the installation of the new screen i did not touch that inductor at all, nor have any heavy bumping of the logic board so it appears this inductor is very poorly soldered in at the factory.

    I suggest that if your having this reception loss issue that you take the back off with the phone still on and try to bridge the gap left where the inductor used to be by lifting up the L shaped ribbon on the bottom left hand corner and using a flat bladed screw driver as said before, if thats your problem a bit of solder in the capable hands of someone experienced should have you out of trouble. If anyone wants help with this pm me. (take the logic board out to avoid damage to the dock/speaker assembly.
  9. LuMe96 thread starter macrumors newbie

    Jun 8, 2011
    Hi Chomby1991,

    very interesting.

    Could you give us the link to the page on iFixit? I don't have a iPhone 4 opened right now and have done some of them in the meantime without any trouble, but it would be good to know where exactly this inductor is located.

    Thanks a lot for the feedback.
  10. chargit macrumors 6502a


    Jan 17, 2010
    Evansville, In
  11. chomby1991 macrumors member

    Jul 3, 2008
    Australia ->queensland ->Rockhampton
    The photos here clearly show a small blue dot (the inductor) halfway between bottom left corner and antenna cable.
  12. gillropar macrumors newbie

    Oct 15, 2011
    THANKS chomby it worked hasstle free...

    firstly a big thanks to chomby he saved my life and i just joined macrumors to thank him.... and to assure all other users who have doubts in their mind "this method works 100%" but be very care full while soldering ,use very less amount of soldering metal and use very thin mouthed soldering iron as it can interfere with the nearby points on motherbord....
  13. chomby1991 macrumors member

    Jul 3, 2008
    Australia ->queensland ->Rockhampton
    Thanks very much for going to all that effort of letting us know, I'm glad I could help someone :)
  14. Nut about Apple macrumors newbie

    Feb 21, 2012
    iPhone blue inductor

    I found a great video on youtube, I just searched- iPhone 4 'No Signal or No Wifi' fix- Blue Inductor/Coil.

    Changed the coil and it fix my GSM reception and Wifi issue.
  15. chomby1991 macrumors member

    Jul 3, 2008
    Australia ->queensland ->Rockhampton
    Well done on sorting it out, but for other people reading this thread you don't need to replace the inductor, my first post explains it all. Btw my phone is still working 100% to this day
  16. kkttoo macrumors newbie

    Mar 16, 2012

    I had the same problem after replacing the screen myself. However, rather than having No Service all the time, I get intermittent 3G signals depending on my location. Generally I get No Service or weak signals (one or two bars) when I am, say, in the basement of a shopping mall. The signals get pumped up to 3 or 4 bars when I am out in the open.

    I have checked the innards according to the points you mentioned. The blue inductor is still there and the connector is firmly connected to the motherboard. The contact and gold metal clips are there as well. So what could have gone wrong? I have disassembled the phone at least twice and cleaned the screw and connecting metal parts but still experiencing No service or weak 3G signals (one or two bars)....

  17. hozone macrumors newbie

    Mar 30, 2012
    same as Brian for me,
    i've also changed the "wifi" antenna, which i suppose is the antenna, but intermittent signal.
    also have to say that i've better signal if i have not 3g enabled.
    if someone has solution please tell :)
  18. cosmiccomputers macrumors newbie

    May 8, 2012
    Iphone 4 Fix

    Please can you show the picture again as the link has stopped working.
  19. Lorennunley macrumors newbie

    Jun 23, 2012
    When this happens there is a gold antenna at the top of the board that isn't seated. All you have to do is take a small flat screw driver and gently push the tip under the frame. Once the tip is seated under the frame, normal signal quality will resume.
  20. hozone macrumors newbie

    Mar 30, 2012
    if you mean this one: http://www.brianklug.org/wp-content/uploads/2010/04/iphone4imageofconnectors.jpg
    i've already checked.
    main problem is that !sometimes! works in GPRS, and EDGE, never in 3G (even if it is enabled), and after a wile i've no signal.
    i suppose there is some solder problem due to a phone crash.
  21. Lorennunley macrumors newbie

    Jun 23, 2012
    Have you tried more then one sim card? I've seen a rash of bad sim cards come through my shop here lately.
  22. Lorennunley macrumors newbie

    Jun 23, 2012
    I need to find a supplier for these gold antennas, I've got three here I've bought with broken/missing antennas. Anyone know where to get them?
  23. hozone macrumors newbie

    Mar 30, 2012
    yes, my sister has a working iphone4, sim works on her phone, but not in mine.
  24. throughhymn macrumors newbie

    Jun 29, 2012
    Can anyone help point to a tutorial or something that explains how to do what chomby did? I too am missing the inductor for my phone but don't know what he's talking about in his solution lol

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