new member, interested in audio and bettering my audio repair skills

Hi all, my name is Trevor. I have been doing audio repair here and there for years now but lately I have been tackling more amplifier related projects which I find much more difficult than other types of audio. As such I am trying to broaden my knowledge on such repairs as much as possible. I generally like late 70s to early 90s Japanese solid state (and adjacent) but I have owned quite a bit of stuff over the years.