This is exactly the service manual I needed.
Complete with all schematics, partslists, PCB layouts and alignment instructions.
This manual covers both the T-4970 en T-488F Onkyo tuner.
Wanting to repair a neighbours tape recorder I needed the necessary information, it makes it easier. Although the service manual is described as "Language : English" To my dismay I found that it is entirely written in German, a language I do not understand. At least I now have the schematics which will help of sorts. I may not use this service again due to the laguage difficulty after all when it states English you do not expect it to be entirely in another language.
Text excerpt from page 6 (click to view)
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PCB CONNECTION DIAGRAM
CC UNIT
A
NOTE FOR PCB DIAGRAMS
1.The parts mounted on this PCB include all necessary parts for several destination. For further information for respective destinations, be sure to check with the schematic diagram. 2.Viewpoint of PCB diagrams