I have a TopHat Super Deluxe Mk2 which has a loose place on the grille cloth. I am NOT "constructionally inclined" to the point where I am comfortable with trial and error in trying to find out how to fix it. Can anyone tell me how to get the grille off so I can retighten the cloth on this amp? I didn't see any visible screws and don't want to take any chances, but if I know how it comes apart, this will be an easy fix. Thanks!