I found the POWER ON discrete code for my (old) SONY amplifier TA-D 505. I learned it with LRN Helper and it reads :
0000 0066 0000 000D 0060 0019 0018 0019 0030 0019 0030 0019 0030 0019 0019 0018 0031 0019 0018 0019 0018 0019 0018 0019 0018 0019 0018 0019 0030 03F2
Since it could be useful for other USB UIRT users, I share it here.