perpetuum-ebner hsv 60T

Hi all , I am looking the schematic or the service manual of the perpetuum-ebner hsv 60T integrated transistor amplifier. I need only the schematic only from the output (power) stage. I have one of this rare unit in very good condition, and one channel can not set the dc voltage correctly. I changed all transistors and elec caps, but the problem remains. So I have to look deeper. If anyone can help with a schematic it will be perfect.
Regards