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.
GOOD SERVICE MANUAL.I ALWAYS BUY THERE IF I FIND WHAT I AM LOKING
Text excerpt from page 46 (click to view)
5-2. Replacing the CPU
1. How to remove the CPU 1 Rotate the lock with a flat-blade screwdriver toward the unlock position shown in the figure. 2 Remove up the CPU. 1
CPU lock position 2
unlock position
CPU socket
2. How to install the CPU 1 Position the mark on the CPU to the mark on the CPU socket and put in all pins to the holes on the CPU socket. 2 Pressing two corners marked with in the figure, rotate the lock with a flat-blade screwdriver toward the lock position. 2
mark CPU unlock position mark 1
lock position
CPU socket
Note: Lock the CPU properly, or operation becomes unstable.