imac Internal Mic not working

[Archeantus]

I have iMac (27-inch, Late 2009) running osx 10.10.5. After setting up and using an external usb mic in garage band the internal built-in mic will not work. I have unplugged the external mic. I have selected the built-in mic in audio preferences. I have rebooted. I have reset the PRAM. I have selected the built-in mic in garage band preferences. I'm at a loss. Any ideas?

 

[Cory Cooper]

Hello and welcome.

-Which version of GarageBand?
-Does the internal mic work in other apps?
-In the Sound preference pane, do you get input levels?

C

 

[Archeantus]

- garage band 10.1.0
- mic doesn't work in any app
- no blue bars in input levels
- input volume at max

 

[Cory Cooper]

Thanks for the additional info. It could be a coincidence that the iMac audio board has failed, but usually the mic isn't recognized if that happens. It shouldn't be a GarageBand preference issue, since it doesn't work in any app.

-Do headphones work?
-Do you have any thrid-party audio routing apps like Soundflower or LineIn installed?
-Have you had any internal repairs/upgrades done?
-Try an SMC reset
-Try changing the sample rate/format for the internal mic in the Audio MIDI Setup app

C