hifi engine

Kenwood KT 5500 tuner-help wanted !

I could get this nice tuner for no money but it does only mono in FM modus.

Are there owners out there who are in possesion of the manual and/or the schematic and would like to scan it for me ?

It is my second "vintage" tuner whit FM broadcasting problems.What is it whit this older tuners that stereo broadcasting fails after so many years ?