Help No audio (or buzzing) with default Android phone application

[Doddibot]

I get no sound when I make or receive calls using the default Android phone application, and the person on the other end gets either a constant buzzing sound or silence. Neither of us can hear the other one speak at all. However, it works totally fine if I use my Bluetooth headset (both parties get perfect sound), but doesn't work if I use the corded earphones + mic. I can also make calls with Skype and that works perfectly using the inbuilt hardware (i.e. no attached microphone/speaker), and Skype also works fine with both the bluetooth headset and the corded headset. So the only incompatible software and hardware combinations seem to be the default phone app and the in-built microphone+speakers or physically attached mic+earphones.

My phone is:
Samsung
Galaxy S4 Active (i9295)
Android 4.4.2

I have reset my device to factory defaults several times. On the first occasion, the issue seemed to have resolved itself but alas it didn't stay fixed for long. By the time all my apps had re-installed it was no longer working. The 2nd and 3rd times, I still had no sound even when making a call immediately after restoring the phone to defaults.

I have also tried using my SIM card in another phone (works fine), and another SIM card in my phone (same issue presents in the exact same manner).

Is there something really obvious I'm missing? And seeing as my phone really does everything else fine, are there any phone apps that over-write the default Android one that might work? I've seen dialer apps but they still use the default phone service to attempt the call.

 

[Doddibot]

As an update, I've found a link to similar issues here: https://code.google.com/p/android/issues/detail?id=82949

Am working through solutions, still no luck as yet.