Alright!! Someone modifying system 7 roms. Any chance that you can make one little tiny modification to the Defender Pinball rom?
This game has no background sound. The sounds exist in the sound rom, but they (Williams) deleted the little bit of code that allows you to turn them on. I believe they were running out of room on the chips and since they weren't going to use the background sound (which matches the video game) it got the ax.