Welcome to the world of cheap voltage regulators. I went through 4 of them, couldn't get one to work for more than a month, and bought an alternator. They are junk now.
Best bet is take it all off, take it to a genny shop, and have him pair it with one of his regulators and make it work good. Then bring it home and put it on. Let him wade through the junk. At $40 a pop you will go broke making that old system work with Chinese parts.