If your unit is like mine on my 320, it pulls out on tracks and swivels. You should be able to unscrew from the bottom and the plug receptacle should be in the back of the enclosure.
Now for the good part and I am planning to do this. Since your flat screen will be smaller in the back, you can get innovative and build something that will have additional storage in the back of where you TV was. You should gain about 14” of storage.