Light strands on modern trees are supposed to stay lit even if a bulb burns out. The theory is the burnt out bulbs should still present a circuit path, even when they burn out, rather than an open circuit. But still, sometimes, the entire string of lights goes out. I spent hours this Christmas trying to fix two burnt-out light strands on our huge, pre-lit, artificial tree, to no avail. I called the manufacturer and they said they could repair it if I shipped it back, but it would be simpler for me to purchase Lightkeeper Pro for about $15 … Continue reading Amazing Invention