Yamaha AVR RX-V677 No response

[MALE20]

Hi, I got a Yamaha RX-V677 unit which I am trying to troubleshoot. Long story short there is no chance to start the unit. Power board seems to be OK however enabling signal that goes to DC-DC converters is not there which means other necessary voltages are not present on digital board (page 93 in service manual). 3.3V and 5.6V from power board are present. I am now puzzled as I don't know where to go from here. If anybody can help please let me know.

https://elektrotanya.com/yamaha_rx-v677_htr-6067_rx-a740_sm.pdf/download.html