Looking for schematic/service manual, for a Sony TA-N7050 power amp

Hi all! I am looking into buying a Sony TA-N7050 power amplifier. Off-course I would like a schematic to go with it. However, searching hi and lo on Google, I cannot find a schematic or service manual for it.

The amp was meant for Studio/Pro audio, and rack mounting. It was built around 1985. Google search here: https://www.google.se/search?q=sony...AgCgAgCYAwCIBgGSBwCgB_4E&sclient=gws-wiz-serp

So, if someone could share the schematic, or can point me were to look, it would be deeply appreciated.

/Urban