[SOLVED] Carnevil board has unstable video on supergun, fine in cab.

[pyract]

I'm trying to hook up this Carnevil board to my MAS-style supergun, and I'm getting this pulsing video problem. I tried the board in my jamma cab and it worked fine. My first thought was power supply so I swapped the jamma cab psu into the supergun but the problem remained. I haven't had any problems with any other games on this supergun, any ideas?

EDIT: To add to this, I also have an Invasion: The Abductors board that works fine in the jamma cab but shows no picture on the supergun. What does work fine on this supergun, is Area 51 Site 4, and all my CPS2 games.

Finally solved this. For posterity's sake:
The problem was caused by Midway boards' tendency to use 53Hz refresh rate instead of 60Hz. The compatibility depends not on your RGB-to-NTSC converter, but your TV. My 33" Panasonic couldn't handle it, but my little 14" Zenith with built-in VCR works like a champ and displayed a crisp, stable picture. Apparently this problem is also common with Sony TV's.