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 106 (click to view)
General Troubleshooting Guide
201B4 M25P 99 Go to cover page
17 A buzzing sound when powering on
This sound is caused when the auto degaussing circuit is active. This buzzing sound is normal when the monitor is first turned on. This sound may be louder during the winter months and during initial power on.