Outgoing sound (internal and optional mic) drops out on iPhone 4
This one is probably for an iPhone 4 expert.
Outgoing sound (my voice), suddenly and unprovoked, drops out during calls. There is a small static sound, and sound is gone. The person in the other end goes "Hello, hello.." and then hangs up.
This will happen no matter what mic is used. I tried all 4 sources:
Main mic (bottom right)
Speakerphone mic (located in headset jack) Bluetooth
And of course, an ordinary minijack headset
Solutions already tried:
1. If I bump the bottom of the phone on a table, or another hard surface, sound will be back for a while, but usually not for long.
2. I have tried to change the docking module, with the standard mic attached to it = NO LASTING CHANGE!
3. I have tried to take the phone apart and assemble again = NO LASTING CHANGE
Both solutions seemed to work for 30 min or so. Then, sound gone again!
I have tried to "irritate" the jack plug, to see if it was stuck somehow, but it didnt seem to change anything.
I have checked all ribbon cable connectors with a microscope, and they seem fine. I could understand, if it was in the big dock-connector at the SIM tray that was causing this, but the coming and going of sound, with bumping the phone don't lead my suspicion to a bad connection in that sort of plug. Especially not since I changed the whole dock module, and thereby also the plug.
It records LONG memos without any problem, so the problem has to be in the "transmission/sending" part of the phone, rather than in the "mic department".
Unfortunately, I bought this phone 2'nd hand, and didn't get a reciept so warranty exchange is not an option. Futhermore, I had in laying on my shelf for a month before I got around to use it, so it's useless to complaint to the previous owner (who, I am pretty sure, knew about this problem, based on the fact that the problem is constant and persistant).
I REALLY hope some iPhone expert can help, as this seems to be a problem that seems hard to solve.
Thanks in advance!