Scrambled image output from Axunworks Cbox Supergun

[Four Wudude]

I'm new to Superguns and arcade stuff in general, but I decided to pick up an Axunworks Cbox. I'm trying to run it on a CRT, but the video signal is unusable. I'm using a DB15 video cable and a cheap RGB to S-Video/ composite adapter (pictured.) What might I be doing wrong? Should I buy a different video cable? Or is my AliExpress transcoder not up to snuff?

 

[Four Wudude]

Update: Bought a different converter and it works fine now. You get what you pay for I guess.