Welcome to the group! You're obviously among those who know better, here. Those who make those claims haven't bothered (or aren't able) to understand how the technology in the Carver amps works, and they prefer to assume a good amp has to weigh as much as a small car to be good.
I won't offer any advice on building or fixing (my knowledge on which end of a soldering gun to hold is iffy at best), but there are plenty of folks here who can help. In the mean time, you have my encouragement to dive back in and have fun, both at the build/fix end and at the all important - "it works, time to listen" end!