Hey,
Just so you know, we had the same issue with the demux a few years ago. Everything would be working fine, then bam, some lights would flicker, go 100% but the desk show no output but the dimmers showing input, i'd lose control and have to restart everything. First i thought it was the desk then then demux. So i had a play with the din cables, unplugged and rewired and it all worked. So during a show I was ordering some new leads to be delivered next day. New DIN leads arrived, plugged in and turned on and it did it again. So I just sent the unit back to Zero88 who bench tested it. Reporting to faults back, touch wood, it's all working fine still. Weird...