Replacing Sony BVM with Makvision Tri-Mode?

I've been running all of my consoles on an old Sony BVM via RGB-sync using a scart to BNC cable.

Now if I want to connect them to my Makvision can I simply use one of those BNC to VGA cables or would it require additional electronics?

I notice that scart to JAMMA converters tend to be a bit more involved than what I just described and really don't want to fry anything.