So, I'm jamming at practice, and something doesn't seem right...the amp (RM100Combo) doesn't seem to have enough 'bite' to it...So during a break, I check it over, and the tube failure light on tube four is on, but the tube is clearly lit, not dim or anything. So I shut the amp down, and check the fuse, and it is BLACK. So, I obviously blew the fuse, and need a new one. My question is, since the fuse is shot, and the tube was still lit, what the heck is the fuse even doing? I used the amp after the fuse went out, so it must not be a big deal. And has anyone else had this happen? I'd like the comfort in knowing I'm not the only person who's done this :-D