My wife's Samsung Galaxy S4 was dipped on water by our little one and she immediately took it out and removed the battery. Phone was left to dry for 6-7 days. When she put the battery back and switched it on, it worked but started making crackling noise on welcome screen and screen unlocking.
Being a techie, I took a challenge to fix it. I diagnosed the following problems.
1. I was able to make calls and hear the person on the other side but he was unable to hear me (possible microphone issue).
2. On hands free, called was able to hear me but S4's speakers were making weird noise.
3. On welcome screen (samsung logo) and screen unlock handset was making weird noise.
I washed it's motherboard with 70% alcohol and replaced it's mic and speaker. Now mic is working but spear still makes weird crackling noise. It works perfectly with car bluetooth and headphones.
Can anyone please suggest me what could be the reason and how I can fix it.