NEO-MVH MV2F Sync problems

Well guys just some days ago I had fixed a monitor that was crappy. Then I have ordered a new one but 29 inch. Hooked it up to my Neo Geo CDZ (RGB bypass modded) and all is worderful. Then I decided to play some World Heroes Perfect on my 2 slot MVS board and then no freaking sync!!! just some damn rolling picture and none of the pots could make it work. I thought it could be the cartridge, cleaned it no help, the I just put every one of the 34 carttridges I do have and all givethe same damn rolling. Checked the damn cables, jamma connector, all the heck and can't find whats wrong. By the way, the Neo CDZ, Neo Front Loading all do work ok in any of the monitors. Anyone can give a little advice?? Or I'll go crazy trying to understand WTF is going on

BTW my PAL Game Cube give this same problem... Just bought it to play in RGB and no luck...

SOLVED

OH GOD let me tell ya guys, after testing cables with multimeter and everything bein ok as a last resort I just made a rgb cable out of some old cabls just for testing and the sync worked. WTF the damn multimeter didnt see nothing wrong and the neo cds and the aes work ok just the mvs that not!!!
Well will buy some neu shielded cable and no problems anymore.

And so as it turned out to be the cable I have decided to try again the PAL Game Cube and found it doesnt work. It seems theres no sync on it. What can be???