mame pc picture problem on arcade monitor

[MikeHaggar]

Hi folks, I just bought a sf2 cab from this site with a 25" wells
gardner k7000 monitor and the picture is good with the sf2 arcade board
that came with it but when I put in a mame pc everything is
slightly ghosted round the edges. The pc is fine in a candy cab but not this american cab. Any ideas as to why and how to fix it? Thanks.

 

[Ste72]

Could be a bit of focus adjustment on the flyback?

 

[MikeHaggar]

No Ive tried that and the arcade board would look off if it was that.