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.
3-3. ACCURACY SETTING SYSTEM
The accuracy of this module is set by Pattern Cutting method (P1 ~ P5) in the production line. Therefore, in case a trouble occurs in the quartz oscillator or the LSI, replace the whole P.C.B. with components with new one.