I decided to use 203 rxi between my gscartsw and BVM. A friend made a SCART to VGA cable (with audio breakout) and i connect it from gscartsw output 1 to extron 203 rxi input, but i'm having problem with horizontal scrolling. I also has Dreamcast VGA to another Extron Input 1 which are working fine.
If you look at below video, the other gscartsw output which go straight to another monitor are working fine.
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