if you have a spare psu take out all but one hashing board and hook up all the pcie connections you have.. they are paralleled on board so it wont matter if you have only one or two pcie as we just trying to troubleshoot for a bad psu... once ya hook it up then see what ya got.. also Im sure ya checked the breakers on the plug outlet also..
ive got several s2 and have run into several issues that ive been able to resolve without sending back to bitmain.. recently being the abitlity to save your settings after reboot.. it was a pain when 2 s2 where fighting for the same ip 192...99. had to keep going to farm to fix manually as they weren't accessable with two on same ip the latest firmware fixes that now... hope this helps ya:D
edit : also check the main line from the psu that would have connected to the motherboard of a computer.. it may have the wire loose that tells the psu to turn on.. similar to what is need to make the psu come on on the antminer s1 setups.. shorting pin 4 and 5 on the motherboard conector to activate the psu.. lookup to make certain on the pins.. ive never had one not turn on to look at how they make the psu activate.. not sure if its a jumper wire or an actual plug adapter..