Discovered two strings with a bunch, but not all lights, out. Did a little online research. Could be a fuse problem. I had to go online just to figure out how to open up the door on the plug. Replaced the fuses. Didn't fix the problem. I'm wondering if the fuses have a specific direction they go in? The damn things are small and it's difficult to tell. Then I find some info that indicates if one led goes out, all the bulbs in that circuit (there are usually two) go out. This is news to me as I had thought that if one bulb was bad, the others would still work. Guess not.