A little while ago I was playing guitar, and I accidentally stepped on my patchcord. The bolt holding the input jack on my Vox came out, and the input jack fell into the amp. I'm sure I could fix it easily, but the problem is I can't figure out how to get into the part of the amp it fell in. I've tried taking out all the screws around it and it wouldn't open, does anyone know how to get into the part that the input jack would have fallen into? Also, does the tube ever need to be changed in the Vox?