The TEAC A-1500's Service Manual was instrumental in reviving this classic reel-to-reel. Not only does it have the schematics, exploded parts diagram and parts list, it also provided mechanical adjustment information that approximate factory default settings.
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.