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.
List of PCG-GRX Series (As of April, 2002)
Model Name
PCG-GRX550 PCG-GRX550K PCG-GRX550P PCG-GRX570 PCG-GRX570K PCG-GRX570P PCG-GRX590 PCG-GRX590K PCG-GRX590P PCG-GRX510 PCG-GRX510K PCG-GRX510P
Service Manual Part No.
9-874-524-02
: Additional Models
This manual and the constituent data may not be replicated, copied nor reprinted in whole or in part without prior written authorization of Sony Corporation.