Unfortunately the controller appears to be a custom job, you can't just replace it with any old sewing machine controller without modifying it. I've bought several items from Vevor over the years and only ever had issues with one - a spot welder for assembling Li-Ion batteries. It kept tripping the circuit breaker when switched on! It turned out to be a poorly designed main transformer so I replaced it with a re-wound microwave transformer that I built. Then it worked as it should with no problems. This issue, by the way, isn't confined to just Vevor, other brands used the same machines with the same results.