Some, maybe all the older sg-2100 models didn't do Usals, I'm guessing pre 2003 or 2002, I had one of them, maybe you have one also. I've had good luck with the Moteck motors made in Taiwan, bad luck with the mainland China ones....dxm-7000 is one of those. I was reading on Sadoun's forum posts from people with the dg240, 280, and 380, you might want to have a look there before you invest more $$. It seems there are no perfect motors.