Mike Elliott service schematics

Here's link for some (I did not try a download) and then there's always DIYAUDIO.

DeKay

Are you looking for the original SA-xxx manuals or NP manuals?

if you have SA amps with blown mosets and don’t want to spend major dollars you can replace the output devices new Vishay IRFP9240 and IRFP240 Mosfets. 
they look different and require a wee bit of creativity in mounting and you don’t have to get Chinese fakes.