Apple IMAC User Manual - Page 113

Troubleshooting Symptom Charts/ Sound In Problems - 31 Sound In Problems 1 Audio recording quality is poor, a high level of background noise is noticeable, or no sound is recorded. 2 Open the Simple Sound Control Panel (found under the Apple Menu). Select CD Quality under the Sound menu to minimize noise on the internal microphone. Did this solve the problem? Yes: If the initial sound in problem was with the sound control panel; the problem is solved. No: Go to next step. 3 Reseat the 5-connector audio cable on the outside of the A/V Interconnect board. Looking a the A/V Interconnect board from the outside, the audio cable is the black connector located on the left. 4 If the background noise continues, install the microphone gasket (922-3679) that provides an improved seal. The gasket is placed on the front bezel, around the microphone opening. Refer to Take Apart, "Installing the Microphone Gasket" or TIL article #58053 for additional information.