TMNT jamma problem

[KonamiHam]

Hi
I have recently become the proud owner of a Teenage Mutant Ninja Turtles jamma board but seem to have a problem with it.
The game plays fine, the sound is fine, the start-up test screen and test modes all show everything is ok, BUT...
The colours seem to flash brighter and darker in certain parts of the game. Most notibly, whenever the screen is scrolling during the game.
The colours also seem washed out and flickery on the title screen and hi-score screen.
The strange thing is, it is fine the rest of the time, for example in the intro, animation sequences, the attract sequence and also on the colour test screen in test mode.
I was wondering if anybody could point me in the right direction? I'm thinking I'll have to send this away for repair if I want it to work perfectly, but thought I would check for pointers here first.
I'm using the board with my own self made rig on a LCD screen through RGB scart. I know it works properly as I have 2 other very similar PCBs made by Konami: The Simpsons and Aliens, and these both work fine.

By the way, I am in the UK, and the board appears to be the UK version as it is called 'TM HERO turtles' if this makes any difference...
I think it is also the 2 player version.

Does anybody know the importance of having resistors on the R, G and B wires when using a SuperGun with scart?
I'm sure I read recently about using something like 75 Ohm resistors on the wires to get the best colours possible?

I'm just wondering if this would help?
Although it wouldn't explain why the other 2 Konami boards work and TMNT doesn't.

Thanks in advance for any help you could throw my way!

[gokun]

Well, if you have similar boards that work fine, and only certain parts of the game are mucking up on you my first suspicion would be a bad graphics rom on the board, rather than the monitor. Especially if all the test screens, other boards, etc are working fine as you say. If you have the capability to burn roms, you could use mame info to find out which rom is going bad on you, and burn a new one to replace it and that would theoretically fix the problem(assuming nothing is wrong with the board itself like a component going out,etc.).
But then bare in mind I'm from the US so I know nothing about scart...still I'm going to go out on a limb here and say this is most likely not a monitor issue.

[KonamiHam]

Yeah, this is what I was thinking.
I've check all the connections etc time and again, so it looks like I'll be sending it for reapir.
Ah well...

Thanks for the help!