Vertical Sync Issues with Wells and Gardner 4900 and Mame

[decibel001]

I using a windows 10 machine with a Ultimarc ArcadeVGA card into and Ultimarc Video Amp, using the WG 4900 Neg H/V sync. I use Big Box as my front end and Mame64 0.203 as my emulator.
I find some Mame games load up fine but will eventually start a veritcal "roll", some games work fine without issue. Some games roll from the start. I have tried altering certain video options in Mame with no real success. When I quit the games my front end and desktop immediately sync back up. When games start to roll I can't get the image to hold even if I adjust the vertical hold pot on the monitor.
anyone else have this issue? any solutions?
I am new here, so I hope this is the best place to post this question.

Thank you.