So I was unloading my GK 700RB/210 combo from my car the other day and heard some rattling inside. I took the amp out and there was a nut, 2 washers, and a 4" circular metal plate floating around inside! Seems like this plate screws onto the top of the transformer(?) and the nut must have gotten loose. Good thing I caught this as it could've damaged some components inside. So what exactly is the metal plate for anyway?