Need help with adjusting a Kenwood TK-140X

Hi all,
I've just finished a repair and overhaul of a Kenwood TK-140X. Finally, I would like to turn the potentiometers a bit to really have done everything. However, I only have a circuit diagram of the device and unfortunately cannot find any adjustment instructions for the preamplifier (which is unusual anyway) or for the power amplifier.
Has anyone ever compared this device and/or documents on it, or can anyone help me in any other way?
Thanks in advance for reading and any help