That does seem weird, I still can't figure out why you powered them down for the night. Maybe you just din't have them set where you wanted them.
So when running by itself on the PDU it powers up just fine. That tells me it's not an S9 issue. You say when both are connected they won't power on.
I'm not familiar with the Bitmain PSU's but my PSU's have their own power on switch. If you have these are you able to power on the PDU then power on the PSU's one at a time?
Your PDU should have plenty of room for what you are doing, and the fact that you see the PSU power on but not the S9 is peculiar. Have you made sure that in all the switching the PCI-e connectors are all secure and that your Ethernet is also secure?
As for the 1600W PSU you tried, I don't know the model but is that the output on 110V. Just covering my bases as I'm unfamiliar with it.
Thanks for thinking about it. I've come to some new conclusions.
Each miner works normally when alone on the PDU.
Therefore, either the PDU is not working properly, or the wall outlet is not working - as in not giving enough power. I think.
I'm going to try to get my electrician to take a look.
Thanks everyone!