Hello! Looking for a schematic for the Krell showcase amplifier. Krell service will not sell me one.

Hello! I'm looking for a schematic for the Krell showcase or S-1500 amplifier. Krell service will not sell me one.
I have a non adjustable DC offset caused by the driver board. The driver board has nearly 60 surface mount transistors and diodes on a multi-layer board. Must be some type of servo-control of DC bias. This is most complicated driver board I've seen in my 40 years of repair. Thank you for reading!