Apple Power Macintosh 7300 series - PC Compatibility Card - Manual (Page 112)

Connecting the Sound Out cable
15 Disconnect the audio ribbon cable from the Macintosh logic board.
This cable is connected near the DRAM DIMM slots. The connector has four
pins and may be labeled “CD AUDIO” on the board.
This is the same cable you disconnected from the CD-ROM drive in
step 7. You will be replacing it with the cables that came installed with your
PC Compatibility Card.
112 Appendix B