Originally Posted by Crossfire
The power supply is for the audio/video control box located in one of the cabinets (mine is on the passenger side on top of the dvd player. This box runs on 12 volts and the plug you mention is the power supply to this box.
This was my first thought too Crossfire. But after looking at this little "power supply" box for a bit I looked over at the TV switch/amp and the amp light was still on while the "power supply" had been unplugged for several minutes. So I decided that wasn't it.
I'll have to pull that switcher out and look. Unfortunately the switcher and DVD player are held down by that magical kind of self stick Velcro that is stronger than the adhesive on it's back. So when I started to pull that thing up it was getting ugly and I decided to stop before I made a new project for myself.