WG monitor interference

[fgh]

I'm mame converting a cab with a WellsGardner 25K7191 using ArcadeVGA (radeon 9250version) and J-PAC, and get a constant interference on the image, in all resolutions.
Here's a video clip: (2,4mb).

I don't know if the interference was here before I plugged in the PC, but my guess is it was.
I assume this has to do with some monitor pots, or bad cabling, but thought I would ask to see if anyone would recognize what's wrong from the video, before I started messing around, potensially screwing things up further.

Thanks a lot!

[Ken Layton]

I'm on a slow 24k dialup connection and that takes too long to load for me to see it.

If the pattern is a 'worm wiggle' or what's technically called "herringbone" pattern then you need a jumper on the game power supply between the "FG" and COM terminals. Also be sure the monitor metal frame has a ground wire running to the frame of the power line filter in the cabinet and that your cabinet has a 3 prong plug on it's power cord.

[fgh]

Thanks for helping out!
It does seem like some sort of herringbone pattern.
I connected the FG and COM terminals without much improvement.
The monitor was already connected to a power line filter, but the only grounded power outlets available are located in the kitchen, so I assumed this was causing it, and hooked it up next to the fridge..
(Just kidding - I used an extension cord).
And it worked! But when cross-checking with the ungrounded power outlet it still worked...
All I can think of is that there was something wrong with the grounding for the CP buttons, as I removed one of the joysticks, (I'm working on the replacement CP) and re-connected the ground the day before the interference disappeared..