Composite vertical scrolling issue

[djcalle]

Hi Guys,

This issue is not arcade hardware related but I hope some of you video gurus might be able to provide some insight about this.

I am having a vertical scrolling issue with my current project. I am building a mini Ms PacMan cabinet based on a Jakks Plug and play tv game and a rearview camera 4.3 TFT screen.






The scrolling is quite slow. It takes about 10 seconds for the whole image to “revolve”

This is what I  have tried so far:

I thought this might be due to the power sources I am using. So I tried to power the Jakks unit with batteries or 5v USB adapter. Tried to power the screen with various 12v PSUs and also tried to isolate the wires with tho

When using the screen with another video source, no issue.

When using the Jakks with another scree, no issue.

I have had a look at both PCBs in hope to find a pot to adjust but no luck.

Is this what is called “ground looping”?

Any ideas of what could be causing this and how to resolve it?

Any input would be appreciated

Djcalle.