Total I brought two of these DA8X but I never have chance to hear the music from it. Here is what I do to make it works:
Details modification procedure (New V4): Yamaha DA8X Modification from Y2 input to AES input v4
Data sheet: YM3436
Draft: DA8X draft notes
DA8X service manual: https://www.synthxl.com/yamaha-da-8x/
Bourns Pot: Bourns 10kA 1874875