Question about electrical box inside project RV

Gdetrailer, thanks for the detailed response. That's what I was looking for. I figured it was obsolete and the old box alone probably dragged down 2 MPG just because of how heavy it is, lol. And yeah I assume the newer converters use solid state switching technology or something like that, resulting in a much smoother, better-regulated output. Much more preferable. I'll disassemble this one for scrap parts.