Samsung Galaxy S4,Samsung problems

How to Solve Samsung Galaxy S4 Network Problem?

How to Solve Samsung Galaxy S4 Network Problem?

Problems

  • No Network
  • Signal Dropping Issue
  • Low Signal
  • Too Much fluctuation in signal strength.

Reasons of Problems

  • Phone might be water damaged or physically damaged.
  • Incorrect network mode.
  • No continuity between Antenna contacts and coils.
  • Power amp IC might be faulty.
  • Antenna wire might be damaged (only for CDMA network phones)
  • External antenna connector might be faulty.

If your Galaxy S4 is encountering any such problems then all you have to do is to go with the below mentioned workaround method or hardware fixes, as they will be able to solve your S4 network issue in the best possible manner. If you are lucky enough then you will be able to solve the issues with the help of Workaround methods. So let’s begin with,

Workaround

  • Restart your Phone and check.
  • Remove and Reinsert SIM card.
  • Check with any other SIM card and verify whether it is the problem with your phone or your service provider.
  • Verify the network mode of your phone, simply by going into its settings. This is important because service providers are either providing CDMA, 4G, 3G and 2G services.

Hardware Solution

S4 antenna contacts coil and external antenna

  • Open back cover and frame of your Samsung Galaxy S4 and check Antenna as well as Antenna Contacts for any physical or water damage (Antenna is at the back side of Galaxy S4 frame).

S4 antenna at back frame

  • If it is found to be water damage then clean and re-solder antenna contacts and antenna. Change antenna if it is faulty and Check.
  • Now Check Continuity between antenna contacts and coil with the help of multi meter. If there is discontinuity in the path of Antenna contacts and coil place jumper, if that doesn’t work then change the Coil.
  • Check external antenna connector for continuity, if there is discontinuity place jumper or replace external antenna and Check.
  • In case you are using CDMA network, check antenna wire for any cut or damage.

removing MMC and Sim Card Strip assembly

  • Now remove MMC and Strip assembly, as the network section is underneath that assembly.

Galaxy-S4-power-amplifier-IC

  • Now gently heat power amp, if it still doesn’t work then replace it.

If all that fails in resolving your Samsung galaxy s4 network problem, then upgrade your Android Operating System, but this happens in a very rare case, so this step should be tried in the end.

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46 Comments

  • Hi Peter,

    Thank you very much for this blog post. I really appreciate it. Clear useful information with pics! I purchased an broken S4 to repair it. I would be in the amateur repair technician category and this was a project. On receipt of the phone it had a broken glass and it had a no sim error and no network signal.

    I have replaced the external antenna cable, lower pcb assembly (usb port etc.), SIM card MMC connector, glass and rear cover (original had damage). I do not have the no sim error any longer but the phone still fails to pick up a signal. Otherwise the phone is perfect*.

    I have followed you instructions above and I can trace continuity from the right hand antenna contact past the coil. I have traced continuity across the external antenna cable. I have even traced continuity from the right most antenna connector to different parts of the phone.

    I cannot find continuity from the left most antenna contact. I cannot trace it anywhere. Should I be able to trace continuity from the left most contact to the coil? To other sections of the phone?

    There is a contact on the opposite side of the main pcb that I believe connects the pcb to the GPS antenna. This contact is damaged, some of it broke off when I was trying to ‘stretch’ the contact (before i found this site). This will need to be re-soldered but do you think this has an effect on the cellular reception?

    I had already flashed the phone to with a newer android version as well as resetting the phone.

    I will heat the Power amplifier next. Is a heat gun sufficient to heat the amplifier? Are there any apps that I can install on the phone/my laptop to help diagnose what might be the issue?

    Any help you give me will be greatly appreciated.

    Thank you very much.

    John.

  • ZORAN ZUCOVIC

    Hi,peter i have same problem with network signal, i have only one bar, i want to replace the antena but i dont no where is the antena,is it where is the speaker is,or is in the back frame?can you maybe send me a foto of antena?thanx

  • I have a gs4. After screen replacement WiFi signal is weak if I push on the area where micro SD card slides on mid frame the signal is normal until I let go. I checked basic contacts? Is there an amplifier underneath?

  • Really awesome work you have here, truly appreciate you sharing the knowledge. Just curios though, when your heating these chips, at what temp and blower speed do you usually set it to. Thanks again.

    • Thank you Marcel for your appreciation. These chips should be heated at a low temperature (which is the melting point of glue) and blow speed should be high. You are welcome!

  • Hamida hichem

    i have samsung galaxy s4 i9505, u have problem with network, the phone work good near the operator BTS , but no service if i am far from the BTS, (since no antenna)

  • Hi there, I enjoy reading through your post. I wanted
    to write a little comment to support you.

  • Hey.. my galaxy s4 is 2 weeks old. Its just working on the 2G and once I put it on the 3G or the auto connect and lock the mobile the network blocks and I couldn’t make or receive any calls.is that a software problem?

    • Well it depends upon what type of services your Carrier is offering. In which region you live in? You need to ask your service provider regarding this. And yes it could be a software issue, but this problem might be from your carrier. Do you encounter similar issue when using Wi-Fi?

  • to solve the s4 signal failure ,just go to settings -network -select-gsm only.the problem is fixed.
    if you selected auto connect lte- 4g- cdma- gsm in this case the phone would switch on and off anytime you pass by or drive whithin low range signal,so to have steady signal just select gsm only or cdma only depends on the network you are using.and if you want fast data then select auto connect but dont drive or move .

  • Hey man great advice btw, but I was wondering if you can help me with a different issue. I rooted my s4 and erased a few things that I thought were safe. Apparently that made my lte turn off. Can you assist me? I’m thinking I need reset the connectivity to antenna or something like that

    • Vladi at first try restore to factory settings, this might do the job for you (Chances are really very less), Try to go with OTA update (but this might also be ineffective). At the end you need to check out the local repair center that does software too in order to get this thing done. Make sure that you go to the professionals in order to get this thing fixed. Also do some research over which apps effect the LTE service.

  • Really useful guide. On my gs4 the top antenna contact has snapped off. This is a link to pictures of the damage: http://imgur.com/a/lNW08#0

    Do you think this would be fixable? Many thanks for any help you can offer.

    • Simon the image you send me was really very helpful, it helped me to understand the problem Thanks for that, and Yes this can simply be resoldered. Just buy an antenna contact and resolder that this will get the job done right for you without damaging any other component! However make sure that you have removed this antenna contact properly with the help of a heat gun. (NEVER Pull it out without heat gun, else you are going to Rip off your Board, and that will be an irrecoverable damage. Use heat gun and tweezers to get this thing done )

      • Can’t seem to buy a antenna contact (as in just the tiny antenna on it’s own) but I can see similar antennas on other parts of the phone. It seems on ebay that I can get the lower board (that has the USB port on) and that has antenna that look pretty similar, could I use those ones as replacements?

        Also, I have managed to find the top part of the contact that was ripped off. Is it possible just to resolder that to the lower part or something?

        Many thanks again, really helpful.

        • Yes Simon! I have seen that link and yes you can buy that! And no you cannot use other antenna’s, as they look similar but they might not be able to do that task.
          Well it depends in what way it was ripped off, if it has damaged the board then you cannot re-solder, but if it didn’t damaged the board then you can definitely re-solder it.

          • Just thought I’d post to say that I finally got around to fixing this. I used an antenna from the micro USB board that forms the other board inside the phone (obviously I purchased another one and that was around £8GBP). Wifi works just as it used to now.

            Thanks again for your help kind sir.

  • Hey mate ,
    Last night my phone was working normal,then this a.m I went to read the news and it said it wasnt connected to internet. Ive soft reset it ,cleared cache, sim card in and out and unfortunately have had to hard reset it . Still my problem has not been resolved . My s4 galaxy doesnt even show a 3g,4g or H+ symbol . Would just like to know if you have any solutions before I have to take my phone apart as I am not too confident with this stuff .

    Thank you

    Any help much appreciated

    • Please check whether your Wi-Fi connection is ON or not, as if you have accidentally turned ON the Wi-Fi then your mobile data won’t work, as by default Wi-Fi is preferred over Mobile data bundle. Check your Wi-Fi settings, Toggle between ON and OFF. If that doesn’t work then do the same for Mobile Internet as well (Toggle ON / OFF), this should do the job done for you.

  • Hey, My Galaxy S4 is a week old and from day one I’ve had issues with receiving my calls and texts. My family and friends will call me numerous times and I wont even receive so much as a missed call notification. It seems to only happen within my house and for hours at a time. But my old Samsung Conquer never had this issue. What could be the problem ?

  • Hi,

    I am experiencing a consistently low signal ever since replacing my screen on my galaxy s4. Nothing appears to be damaged. Is there anything in particular that could cause this? Thanks.

    • Well screen rep;lacement has nothing to do with signals, however i recommend that you give your phone a hard reset. Also remove and clean your Sim Jacket contacts as well as your SIM card contacts. Besides that, I also want you to check with any other SIM card, in order to check what’s the real cause of problem.

  • Hello,

    After repairing my broken screen with a new front end of the phone (Basically everything forward from the mother board) my phone was experiencing lower than average signal everywhere. As an admittedly inexperienced phone repair person, I had accidentally bought a i9505 screen instead of an i337. on the i337, the slot there is a slot beneath the antenna contacts on the motherboard, which is not present on the i9505, causing the case not to close fully and probably doing some sort of damage to the antenna itself.

    Since I spent some money on the screen, I decided to do some alterations and managed to carve out an area in the screen back so the antenna to sit properly. For approximately 5 days, the phone worked as normal with full signal strength, but eventually reverted to a weak signal.

    After spending some time examining my phone, I see no real damage at all to the motherboard, and I swapped out the external antenna and that made no difference to the signal. Everything else on the phone works perfectly. Have you ever seen symptoms on a phone like this and do you have any suggestions to narrow down the point of the problem.

    As I said, the phone works, so I don’t believe there are any continuity issues on the motherboard. It also seems unlikely to me to be the power amp, since it wasn’t in an area that would be affected by the screen swap or the alterations I made.

    Thanks in advance.

    • Adam it seems more like your antenna contacts are not making proper connection the antenna, and this could be the problem. I recommend that you gently pull up the antenna pins with the help of a pin so that antenna contacts are in proper contact with Antenna pins. I hope this solves your issue. However there was no need of changing external antenna in this case.

  • Hi, i walked into the ocean with my galaxy s4 accidentally. I went to fix it in a different store and it got fixed. But now i have 0, 1 or 2 bar reception. What can i do to fix it?

    • First thing’s first, check with any other SIM card, most preferably of some other company and check whether your SIM card is faulty or your phone. If that fails then you need to remove body of your phone and check for any traces of water damage, also gently heat power amp IC and clean all the antenna and antenna contacts and check. If it is due to water damage then this will surely solve your problem.

  • Hi when I turn on my S4 I get reception for 5-10 minutes, I have around -80 dB then it goes to -113 dB and I get no signal again. Seems to work for about 10 minutes or so every time I turn it off and then on again. I opened it up and unhooked the contacts and antennae and then reconnected them. Is it likely to be a hardware problem if I get signal for the first few minutes of the phone being started? Any suggestions what I should try first?

    • If every time you restart your phone and you get the reception for 5 – 10 minutes then it is more likely to be a software problem rather than Hardware. Gregg you need to do the following things: Check with any other working SIM Card, Check your current network settings, go with a software update, Restore Factory Settings. Follow the above mentioned steps in a step by step manner I hope these steps will be able to solve your problem.

      • Hi Peter, I have actually tried those three things. Also, occasionally my phone has signal for a day or so and then loses it again for a couple of weeks. Sometimes when I restart it in an attempt to get signal for a bit, it says that I need to insert my sim card (which is inserted). Any suggestions appreciated!

        Thanks,
        Gregg

  • William Spires

    Got a interesting problem, the internal antenna jack for S4 that came into the shop today has been ripped off the board. My question is how can I use an external jack either r1 or l1 (3g/4g) internally

    • William can you share the picture of that ripped off internal antenna from the board, as only then I can recommend you something regarding that.

  • hiya what are the two contact’s on the top of the sim slot,(they line up with a pattern on the battery cover but pattern is emty looks like a slot for a membrane for an antenna) is there an external antenna that we can just plug in to boost signal while in a dock for instance in my work desk. thanks

    • No Lee you can’t plug anything in external antenna to boost the signals, as it is not designed for that. External antenna has only limited purpose, but if any of them is damaged then you will encounter different network issues. So inshort you can’t do anything with external antenna to boost the signals.

  • cal scott

    I also heard that the sim pack connection lead to the motherboard is quite weak and tempermental leading to no simcard inserted error. Would you be able to show us how to strengthen that connection so my phone doesn’t constantly say its unable to read the sim card

  • noob question. How do i do a continuity check with a multimeter?

    • Mike Place one multi-meter node at the positive terminal of the component and other at the second component (For checking continuity between two components) if you hear a sound like “Teeeeeee” after it is connected then it means that there is continuity between two components. If you don’t hear such a sound than it means track is broken or any of the component is damaged.

  • Hi there,

    While attempting repair of the oled, I have (totally) destroyed the contact on the motherboard that you identify above as the External Antenna.

    Without the antenna wire attached to the motherboard I am getting no reception – is the only solution to solder the antenna wire onto the contacts of the motherboard (and I assume there are two)?

    I only ask, because if you are correct and have identified the external antenna, is there a chance I have done something else wrong and the S4 doesn’t actually need the external antenna to function?

    Any help appreciated

    cheers

    Pete

    • Well S4 needs an external antenna for sure. Well the contacts on the board that i have showed you are actually the contacts of main antenna, while the external antenna wire is plugged into the external antenna contacts, and you surely need both primary and external antenna in order to get reception.

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