I haven't had any problems like this with the 990. Since you already unhooked the amp, the only other thing I could suggest is to unhook everything else from the 990 and see if the shutdowns still continue. If not, start reconnecting devices one at a time and see if one creates the issue. If it still shuts down without anything connected to it, there has to be a problem with the 990 and I would contact the Outlaws. I'm sure they will get you fixed right up. Their customer service is fabulous.