Randy--not an expert here, but I am successfully running two E682s in multicast. I recommend that you download SACNView and "watch" what your universes are doing---for example if you run an SACNView channel check, it will cycle through your pixels from start to finish--it will generate the test signal AND it has a viewer that shows you which channels are being cycled. Even better, probably, is to test some of your elements from XL and watch the channels in SACNView. My two cents. I hope you figure it out!!