Check and wiggle the connector for red on the C-drive board. Either the connector has a cracked solder connection, Or that channel of the STK chip has gone. Either way, it's usually an easy fix. Been discussed to death on the forum. Welcome to AVS, and congrats on the PG. If this is new to you, I STRONGLY suggest you download the tinman/feathers setup guide here, and get a manual for the beast. Most questions regarding NEC's have been answered here, so a search should dig up info you need.
Marc
Marc