Why is my Antminer S9 only using one Chain I have 2 AntMiner S9's running. Each of them appears to be operating only at 4.9 TH/s. All 3 of the ASIC's appear to be in good shape, though each of the miners is only using a single ASIC board.

Key config items:
1. I am using Slushpool on one Antminer. I'm using Antpool on the other. The pools are showing at least one live pool server.
2. I see all ASIC's showing positive status.
3. They are set up in a pretty cool room (10-deg C) with sufficient power

I looked for support on this and I don't see it anywhere--is this a hardware issue? It looks like it isn't as the boards are all showing ok?
Also posting as an answer: the issue is that the GH/S (RT) on board 6 and 7 is 0--it is because the power quality coming into that dedicated power supply is too low.

The board has an ideal measurement (~4TH/s), no busted ASICS. After doing about 3 days of testing, it appears that the power quality upstream of the ASIC boards is pretty important. Even if the power supply is powered on (and reads the appropriate voltage), it is sensitive to the amperage rating of its circuit (I use 2 PS's, one for the main board + 1 ASIC board and a second one for the 2 other ASIC boards).

By moving the 2nd power supply (the one powering the 2 ASIC boards) to a high capacity 20 AMP circuit, everything works. (although now I have a huge power cable running to my miners from a separate circuit). I had to have an electrician come and pull that separate circuit from my main.