No, it doesn't work that way, the only thing before the fuse is the cord, and a bad cord isn't likely to blow a fuse in the amp. The fuse blows from an overload after it, and protects you from burning down your house. Something was failing in the amp which caused the 3 amp fuse to blow. The original owner replaced the fuse and it popped, so he put in an oversized fuse. The 10 amp fuse held, and he decided it was best to unload the amp before it quit working altogether. You got it home and whatever was failing finally went pffft! The amp is dead. You can't figure out why it won't turn on based on the information and experience you have. Nobody could. Someone who knows how to read a schematic and operate a VOM needs to dig into the amp and figure it out. Gutting it and rebuilding it is the most expensive way to go, especially if you have no amp building experience. You're likely to spend way more money than if you bought a new amp, and the probability of the amp working once you're done is small. Read through a few first time build threads and decide whether you're willing to put in that kind of time.