Often times mine refuses to fire. Yes, I checked the connections. In fact I put a voltmeter on it and it's getting power but still won't always fire. And yes I checked the atomizer and it is fine. Sometimes if I re-tighten everything it will work again but now it is sitting on the table completely useless. It's as though it gets voltage but doesn't allow for enough amperage to power the atomizer. I've had this problem off and on for some time but now nothing I do brings it back to life. Good thing I got an el-cheapo mod from fasttech that works every time.