hifi engine

Nakamichi TA-3

I received Nakamichi TA-3 for repair. The problem is that the green Led flickers when switched on. Must be some overload protection message.
This unit is quite bulky to work without a service manual.
The relay on the main pcb does not switch on. There is a standing voltage of 38v on the coil but no load to ground to activate the relay coil. Outside the unit, with an external supply voltage, the relay is working fine.

I would appreciate it if anybody can help me with a schematic or service manual.

Greetings and thanks