sudomod

Hello all,

I am nearing the end of a Gameboy build using a Raspberry Pi 3b+. I am using monitor from a vehicle backup camera system. The screen works, but there is a pretty obvious, pretty ugly problem where diagonal lines are constantly moving across the screen. It's most obvious when the screen is dark black or grey, but can still be seen in gameplay if I look for it.

Here is my best attempt at a picture of the problem:
https://photos.app.goo.gl/EoSEHtvUgvKSxgUcA

Does anyone have any idea what could be causing this? Is my cable too long? Are my monitor settings bad? For reference I am using the following composite video settings:
sdtv_mode=2
sdty_aspect=1

Could this be caused by bad resolution settings? Also, it's worth mentioning that the monitor control board has two composite wire pins, but I am only using one of them. It doesn't seem to make a difference which one I use. Should I be using both somehow? Any help would be appreciated.

Just use one composite output. Some of those screens also just arent that great.

One thing worth noting. I always ground the screen as close to the signal output wire as possible. On the pi zero there is a ground pad right beside the tv pad. Not sure about the pi3. But I'd try to move the ground closer to see if it helps.