Could check if you could spread the load on the multi rail properly. If you tried to put the whole load on one rail it will shut down to self protect. Ironically lowering your clock when i mentioned you were probably trying to run full clock on a undervolted S1 would of probably given you the best hashrate 
I believe that's what I did, could I modify a molex that's on another rail? I'm not sure how to tell.
As far as undervolting/underclocking I'm just trying to get it to run as if it were stock, I'll deal with all that later.
In my first post you could see I was getting a lot of HW errors running a full clock on it while it was undervolted. Was that probably why?