I wonder if a ground loop isolator might fix it?
Just googling what this is set me down a bit of a rabbit hole.
Looks like I also should make sure that the sound board itself has proper grounding. Check to make sure all the screws are intact and then also make sure all the mounting points are clean with no corrosion.
This is also the opposite of some information I found that said to add isolating plastic washers between the sound board and the mounting panel (grounded).
However ensuring all the screws were in place and ensuring the melting points were clean seemed to be the better choice as this is how the game was designed.
Info here .
| Forum Topic by ChadH
pinside.com
Thanks for the heads up and I will start by having a good look at my soundboard itself whenever I get some time....kids limit pinball time