I’m afraid you are going to need to open it up to access the adjustment. This is explained in the service manual at https://beomanuals.com/manuals/Beogram/Beogram%206002/Beogram_6002-Service_Manual.pdf. You can also check out Rudy’s video on opening it up at https://beolover.blogspot.com/2017/07/beogram-8000-opening-beogram-to-service.html.
