Half Section of Pre-lit Tree Lights Out?The bottom part of the top piece of my pre-lit tree went out. These lights are wired in parallel, so if one goes out, the others stay lit. The whole top section is on the same strand and I've checked every single bulb in the bottom part that is out and they are all securely in the socket. I've even checked the fuses, although the top of the strand is still lit. If I remove one bulb, the whole strand goes out. If I replace a bulb in the section that is out with one I've already tested, the section still stays dark. It doesn't make sense. I don't know what else to do. Any suggestions?