Why can't I hear anything during calls on my Galaxy S4?

[Android Central Question]

I've had this S4 with Android 5.0.1 since 2016. It worked fine up until a month ago, when this really strange thing started happening. Whenever I call or receive a call using the regular phone app, I can't hear the other person, and the other person hears this loud high-pitched noise (it sounds almost like a siren, it's awful). This happens no matter who I call or calls me, even if I try to use headphones while making the call. The sound works fine on everything else, like for watching videos and listening to music. Even calling over WiFi (like through Messenger or Snapchat) works fine. It's just with the phone's actual phone call app.

I've reset the phone twice, first time it worked for like 2 calls then went back to the problematic state. Second time I reset it, nothing. I've taken out the SIM, blown on it, blown at both microphones and tried to carefully pick at it in case there was any dirt. Though because calling over WiFi works, this makes me think it's a software or network issue. Help please?!

 

[B. Diddy]

Welcome to Android Central! Does this also happen in Safe Mode? https://support.t-mobile.com/docs/DOC-27781

 

[potterhead4vida]

Hi, I'm the one who posted the question. Yes, it still happens in Safe Mode.

 

[B. Diddy]

Are you able to swap the SIM into another phone and see if the problem still occurs? If it does, then it's either the network or the SIM card. Otherwise, I'd suspect some issue with the phone radio on your phone (which would explain why calls still work on VoIP platforms).

 

[potterhead4vida]

Hi B. Diddy, I apologize for never getting back to you. Life got in the way and so I sort of just tolerated this issue until now since making phone calls with my phone wasn't a top priority for me. This issue still exists, and at this moment I tried swapping out the SIM card for another one. The phone with my SIM card works fine. My phone, with the new SIM card, does not work unless I boot it up in Safe Mode. After switching the SIMs back to their original phones, my phone will not work even if I boot it up in Safe Mode. If the issue is with the phone radio, what do you suggest I do for that?

 

[B. Diddy]

I'm not sure it'll be worth pursuing, since this sounds like a hardware problem, and diagnosing it and fixing it will probably cost more than the phone is worth. I'd consider getting a new phone -- the S4 is a very old phone and isn't very secure any more.

 

[potterhead4vida]

Yeah, I figured that would be what I would have to end up doing. Everything else about the phone is still great, but I suppose it's time to let go. Thank you for all your help though!