Just curious. I installed my FF system in JD last night. The existing speakers (looked like an original setup) was there, but the ground wire had been cut off at ground post and removed. So it was never there since I owned it. I installed the FF setup last night and everything sounds good. I did notice one or two times I opened the coin door the volume stopped and the game appeared to freeze. On reboot it was just fine, with the door closed it's just fine.
Obviously it's easy enough to add a ground wire, but just wondering (since it has not been there) am I risking serious damage to sound boards or other components not having it? thanks