Apple IMAC User Manual - Page 95

Troubleshooting General/ Video Flow - 1 3 Video Flow Video signals begin on the logic board at connector J16 and travel to connector J2 on the A/V interconnect board. The video signals then travel out from connector J5 (on the opposite side of the A/V interconnect board) and continue on via the internal RGB cable to P301 on the analog/video board. From there, the signals are transmitted to the CRT where they are displayed on the screen. Click here to see an animation of how the video signal travels through the iMac. Sound In Flow Sound coming into the iMac system originates at the internal microphone located in the top front area of the system, or through an external microphone connected to the logic board. If the sound signals originate at the internal microphone, they travel along the long internal audio cable to connector J6 on the A/V interconnect board. The signal is then transmitted to connector J1 on the back side of the A/V interconnect board, travels via the short internal audio cable, and finally arrives at connector J14 on the logic board. If the sound signals originate at an external microphone, they travel directly from the external microphone to the microphone (sound in) connector on the logic board. Click here to see an animation of how the sound in signals travel through the iMac.