Thanks everyone for the Help got mine yesterday and after a resolder of the RGB socket and finding the Auto button the GBS is working a treat.
Got the cable soldered last night plugged in the screen was moving from left to right and losing sync so looked up some forums turned out not to be a power issue or a cable issue but the Auto button needed used to sort out the issue. big Smile from me. All I need now is a box for it using the A4000 psu to power the gbs
LOL well spotted no prize mind you! I had the Mega drive laying around its never gonna get used as I have no interest in it so this was the perfect thing for the GBS. I was really panicking because the screen kept losing sync and moving but a quick press of the bottom button marked Auto and all is working.