hifi engine

Luxman R-600 Receiver

I recently bought a Luxman R-600 Receiver on the second hand market. It is in a sorry state cosmetically and there is a distinct [mains] hum through the speakers when powered on, so I will attempt to repair it.
Therefor I am looking for the Luxman R-600 Service Manual, especially the circuit diagram, to facilitate fault finding. Can anyone help?
Regards, Fil800