Having an interesting/annoying time with my n7105.
Dropped it one too many times, and the headhphones audio turned into a static hissing mess!
I found that by just smaching the phone against my knee or something solid, the audio would return for about an hour.
It got worse and worse and eventually I decided to fix it. I purchased a replacement audio receiver jack and installed it, but the problem still remains, so I'm unsure where the actual issue is occurring.
I found that by tightening a screw just below the audio jack, that it fixed the problem. I have to tension it just right... Too tight and the issue returns.
I think the issue must be with the connector on the motherboard, where the ribbon cable connects. I say this because the screw I'm tensioning to fix the issue sits pretty close to this, and would be pressuring this down and around.
So I'm not sure how I'd fix this without replacing the entire motherboard.
I'll crack it open again soon and have another dig at it.
---------- Post added at 10:33 AM ---------- Previous post was at 10:01 AM ----------
I've been doing a bit more research and found that someone may have already done the work for me.
I'll attempt this and report back with the result.
Post from Android Central forums
After my earlier rant I opened my phone and have managed to fixed my knee smacking problem. The problem was a bad ground between the screen and motherboard. I have added a picture of the two metal surfaces I cleaned (circled in yellow) to get the good connection back. These are not pics of my phone because it was apart obviously but it is the same phone. My sound is 100% crystal clear I believe the problem comes with dropping the phone and the connection going bad due to lack of enough screws in the area of the connection. I also ran the screw directly into the motherboard instead of through the plastic backing in the same area I circled. Stop smacking you're phones!!