Need: Luxman L-560 Schematics

I am trying to help a friend to fix the Luxman L-560 unit he owns, for that we need Schematics.
Any chance someone here can put his/her hand on it?

From a certain period in the late 80's there were a few Luxman models for which no schematics have surfaced until now - go to
Obviously the L-560 is one of this models - even under
isn't mentioned a service manual.
Interesting to know would be the reason therefore.
Maybe it have to do with this: "In 1984 Luxman became part of Alpine Electronics" - go to
thanks for the detailed explanation !
maybe one of the members from Japan can find out in his own country, from where this in Europe not released service manuals are available.
E. g. this member:
send a PM.
Maybe he can contacting this nearly 100 years old electronic/audio magazine from Japan