Original post by: mayer ,
The cable you are having problems with has nothing to do with the sound. It is the connector for the optical drive. I suspect that you have failed to fully seat the audio board. Go back and reseat it. Here's how: [guide|1113] Also, after you have reseated, let us know if there is no sound. Go under the Apple to about this Mac > more info > system report > Hardware > Audio and let us know what it shows.