Having same exact problems ... I've seen it on a Zeus v1 and v2 ... but mostly on v1. Got me v2 working but it seemed to take two tries. Not sure what the magical fix ever was. I did change power supplies as I had some newer supplies that turn off when the power draw is lower and those just don't work with zeus ... but typically work ok with active hubs which have some constant draw. In my latest problem, its happening on a zeus v1 and I'm only using 6 of the 16 channels. It worked flawlessly for a couple weeks, then a sequence suddenly turned everything ALL ON ... white ... then I had to reflash ... and tested all ok, then went back out ... and same thing happened, all on ... then later went off all the time. Passes a signal through no problem to the next zeus v1 which works fine. I'm so annoyed with this that I'm probably going to convert those 6 to use a SSC v4 instead and just move on. Luckily for me, its happening on a 24 channel megatree and its only affecting the last 6 ... so they are all on a far side and not really that noticible as the tree just appears to end earlier than its supposed to.
I always recommend trying a new cat5, change the order in which you connect things (it matters, I've seen it, can't explain it) ... check termination of unit and all upstream units (very picky sometimes) ... and also make sure power cables are good and dedicated.
Ironically when I went to pull my controll out to reflash it, I found the supply cat5 had been chewed into 4-5 pieces by a bunny. I believe this happened after the failure, so strange that the bunny hit the same controller which was already not working ... but ok, easy enough to replace the cable. Sometimes you feel these shows are a battle against everything, including the weather and the rabbits ....