Audio Analogue Puccini Settanta schematic or service manual needed

I am looking for the diagram for analog audio puccini stettanta.
I have one on the table with an underlying problem and I need the diagram before dismounting it completely to access the underside of the pcb.
I sent an email to Audio Analogue but no answer and unfortunately, the diagram of Puccini settanta is very different from other puccini.
 
I don't have a schematic or service data but what is the issue? There were a couple of faults that required service, according to some owners. A common one was failure of the standby power supply (The amplifier would not start at all) and required a replacement supply more than once.