That was the fix, I guess the Dreamcast was trying to send a combined signal….or the projector…actually, I don't know why..and after such a long battle, 2.5 years..I'd like to know exactly what it is..
anyway, I can now play Dreamcast on my projector using RGB and Sync(H input) (combining the two H and V signals)
I appreciate everyone's help, and I can state, I did succeed!
I can also now play Sega Saturn through an XRGB3 !!!!