Bump n jump wavy picture/ vertical roll

[KLOV]

Working on a bump and jump cocktail. When I purchased it, the game works, but the screen has a little bit of a waiver, kind of like a rolling wave on the ocean. It also has a hard time holding vertical hold. I guessed this was the chassis, however, I purchased a refurbished one here and upon installation the screen display is exactly the same. Having ruled out the monitor, any advice on what could be causing this.? I can post a video if it helps.

Source: https://forums.arcade-museum.com/thread ... ll.533378/