iPhone 3G - mic suddently stopped working (headset hands free not working either)

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Dave Krum

New Member
Sep 19, 2011
2
0
1
#1
Hi All,
First question on this forum. I have an iPhone 3G model MB704LL. My kid used to use it for games, internet, music, etc and beat it up to the point the volume and power buttons weren't working. So I completely ripped the phone apart and replaced the entire back with a whole new assembly from ebay complete with all the working buttons, etc (everything needed for phone except LCD, front digitizer/touchpad, and the main board). I put it all back together and it works fine except I noticed a few days later that the mic isn't working at all although the speaker is. I figured it was the dock connecter and bought a new one on ebay and put it in last nite. Same thing! Everything seems to work EXCEPT the mic (I've tried the Voice Memo app and when recording and I talk into the mic (right side on bottom of phone right?) there is no audio being input. I read some info on here about putting the Apple headphones with mic built in in the headphone port and then trying the app through the mic in the headphones. STILL NO GOOD. So now the phone is basically useless to me unless you guys have any other suggestions. Please note that the mic DID WORK originally before I took the phone apart so I have to assume its not a hardware issue, maybe software or a grounding problem on the board? I originally had it on 3.1.3 FW with 05.15.04 baseband and JB (originally downgraded FW but too late for BB). I had trouble restoring so I had to go with the latest 4.2.1 FW from Apple and current 05.15.04 BB. It is NOT jailbroken presently and is on 4.2.1. Any ideas on what else to try? Thanks so much!
Dave
 

iphonewarrior

Moderator
Moderator
Apr 11, 2008
13,847
700
113
#2
I don't think it's software if you've restored and you're still encountering the same problem.

If I was in your position I would strip the phone down and make sure all my connections associated to the mic/dock assembly are seated correctly.
 

Dave Krum

New Member
Sep 19, 2011
2
0
1
#3
Thanks for response. I've restored several times through Apple to their latest 4.2.1. Its the completely legit firmware with no modding. The thing is that the mic worked previously when it WAS JB at 3.1.3. I've tried 3 different new dock assemblies and assured that the connector is seating firmly but still no mic. The speaker on left does work however. I'm out of ideas. What about that little grounding clip just above the dock assembly? I'm not sure what that has to make contact with but mine isn't right now (when teh digitizer/screen is off of course).