Silvio at first option didn't work for me either. I failed to establish communication. Regards
This amplifier model uses the IR2156 + totempole as a pwm. When I checked it it had damage in the whole hot part since they insisted a lot to turn it on, aggravating the situation of the machine. Now I don't know what to do with so little information about it
I think repairing this amplifier will require you to do the below
1- Determine where is the problem exactly, in the power supply section? in the amplifier section? in both?
2- Either way you have to take that heat sink off the PCB in order to see things clearly.
3- If the SMPS controller is IR2165, witch I think its not a correct part number, check the schematic for that chip, replace all the parts surrounding it
Also, replace all those damaged SMD resistors, you can get the default values from the internet or the datasheets.
4- Your first test should be WITHOUT the power mosfets, power the amplifier and see if you get regulated 380V
Idont think this is going to be an easy repair for you if you dont have a plan how to start fixing these amplifiers, I usually spend countless hours fixing them, that why I charge my customers lot of $ when repairing them
Good luck