I recently installed a HDD in the optical drive bay with the OWC adapter.
It's not the first time I've done in with a Macbook, as I also did similar with a 2010 MBP 13" successfully.
This time however everything works fine except for the sound. I always get a startup chime, but quite often when booting into OSX the Speaker icon in the top right of screen is greyed out, and when I enter System Preferences the speakers aren't listed as an option under Sound -> Output.
Occasionally though, and it seems more when I boot the MBP on soft surfaces (carpet/bed), the icon is black and the sound works fine. I've tried to look for loose internal connections to no avail. Everything else, wi-fi, camera, bluetooth, mic and external port for sound still works - it's only the built-in speaker sound.
Can anyone give me a pointer as to what may have gone wrong?
Thanks!