Quoted from camcamaro1991:
Sorry, Yes it could be the white-star board, is there any battery damage?
So you saying "ONLY" midrange/subwoofer is making the noise, the speaker mounted on the bottom?
I will look through my manual to see where there might be an issue around the J7, have you tried moving the speaker wires around to locate a possible failure allowing interference?
Its the holiday here in the US I will be busy for the next 2 days.
I have actually tried installed two completely separate sets of speakers (factory and Pinball Pro) both with their own wiring, and the same issue.
I was doing some work on the Balrog toy, and I broke one of the bulb bases which I think caused the short in J7. I ended up cutting the bulb socket out, taping up the wires (until I order a new bulb socket) and replacing the fuse (F7).
However, when I turned the game on, the buzzing was still going on, which I'm now not sure if it was connected at all to the issue with J7, or if it's totally unrelated.
And yes, the backbox speakers (2 speakers) sound completely fine, but the sub (cabinet) has a loud buzzing sound with no audio playing (or at least none that you can make out over that buzzing).
Thanks for looking into this