Happy to find finally a schematic for this amplifier. The schematic is of good quality, the pcb layout is useless: all is black. Never the less, it is very easy to find the components on the board using the schematics.
Hard to find manual was ready the next day. Scans were very legible (including schematics). All the essential parts of the service manual were present (adjustment procedure, schematics, and parts list). It would have been nice if the rest of the manual was included (disassembly procedure, theory of operation, etc.).
The Service Manual for the Kenwood KR-V55R provided by owner-manuals.com was as described/advertised. The contents provided the necessary information to effect a diagnosis of the unit. The schematics above all else was instrumental in tracing the the signal flow from component to component.