Questions about CPS2 Q sound


I made the supergun myself with a RGB->composite adapter card. It works perfectly at the begining. However, just few days ago,I found I can not get the audio from the two RCA jacks in the bottom board of CPS2 system. Well, I tried to connect the speaker with the 2 audio pins on the Jamma harness, then I got the mono sound.
I wonder which part of my system has the problem. The top board or the bottom board or the supergun RGB adapter?

PS: I have acivated the Q sound in the game menu.

Thanks in advance!!
Your suggestion will be great help to me!!!


Does anyone can answer my question?


Does anyone can answer my question?