Some Chinese fixtures don't come with much in the way of (or any) instructions. If this is the case, raising a specific fader may signal a lamp to turn off (or on to restart) at a specified DMX level. It is usually a fader at or near the end of the chain of control faders. I've had customers bring lights in with that "feature" (or problem) that they didn't know about. I've also seen a lot of problems with the nylon covered "butt" crimp connectors, especially those located in the moving yolk portion of the light. The connector wasn't crimped tightly enough and some wires pull out with a very light touch.