I have a similar issue. My sprites have lines through them. I replaced the 6148s because I read that those can be a problem, but still no change. I think mine is a bootleg because it has a daughter board for the 6148s, which seems incorrect. I plan on taking my logic probe and seeing if anything...
I have all the parts, including new replacement buttons, side art, color matching paint, and T-molding. I didn't realize it had DK Jr. Bezel and marquee, that's my fault.