it might help if you tell some of the knowledgable people around here what your problem is and what sort of amp it is, and have you had any experience with high voltage, and maybe an amp tech might be the go if it's your first time???
Dont get me wrong i am not a knowledgable person, I like you am trying to learn, but if it is a tube amp then the dangers are real, so i would do a seach on the web about that, aiken has good stuff on the dangers of tube amps.
have you tried schematic heaven for a schematic?
hope this helps a little,