Are those breakout boards linked together? Not sure about parallels break out boards but other setups that are similar to this such as a 750w + 1200w psu can be used to power an S9. No need to link the breakout boards. I use the 750w for the control board and one hashboard and the 1200w for the other 2 hashboards. This sounds weird but the correct way to fire it up is to turn the 750w on first and then quickly following turn the 1200w on next.
Either way If both these psu's are 750w and you are running on 110v I would say thats not enough, your stressing the psus to much. They might be able to do it on 200+volt but even then I would recommended (2) 800watts or like I said a 750 and 1200.
Hopefully you get it sorted out and no damage to the machine occurs.
The BOB's were linked together (only 2 boards powered) and it went into a red fault. Then I tried only powering 2 hash boards with the bob's not linked and I got a dimmed digital readout on the 1 bob and then the one psu failed. Just curious, if you have 2 psu's powering 3 boards, and the PSU failed that is connected to the control board, what will happen to the S9, any damage?