MUCH less knowledgable still, while waiting on experts, but I just got my first cab and had the opposite problem. Picture was too wide no matter what I did.
Turns out that there was a ‘narrow’/‘wide’ jumper on the chassis. Just needed to move the wire over.
Sometimes there is a horizontal width coil that can be used to adjust the width, usually looks like wire coiled around a plastic tube, sometimes has a knob to turn other times you need a plastic adjustment tool to stick it to turn.
if the horizontal width coil doesn't cut it, there is also a cap in this circuit which you can replace with a higher or lower value to change the width. It's usually a chicklet cap near the coil.
You shouldn't need to adjust the horizontal width coil, and even if you do (with a correct sized plastic allen key), it will probably just break anyway.
Depending on the monitor there's also sometimes a "shift" jumper to adjust the picture position.
Cheers guys the monitor is a tatung type 58 vga monitor vt-2040B, the width coil looks like a cap and haven’t changed it and there is no way in adjusting it, I’ve played about with the different horizontal pots the frequency, phase and width pot doesn’t change anything. I changed the width cap by the flyback from a 680nf 250v to a 560nf 250v cap and it made it a tad wider but a matter of mm.
Like iamjimi said width coil.. it is the copper coil on chassi
Width coil but you want the plastic tv adjustment tool
As there is a fragile core inside the copper coil that a metal screw driver will break it.
If I remember right it is a flat type slotty I when attempting to turn it slowly and carefully.
Also and first try the width pot on chassi as width coil “should” be factory set in middle
Is your street fighter original or bootleg ?as that can through up image anomaly’s
Have you tired adjusting settings on the Gonbes to increase the picture width?
Also not sure about xbox360 with VGA as never had one setup before but is there anyway to adjust overscan settings on the xbox when configured for VGA output.
EDIT: Is this the same chassis as yours? I think the red arrow Ive added to this picture is the horizontal width coil if its on your board. Its a bit hard to tell with the zoomed in pictures you have posted instead of a full one of the chassis.