Mine was shutting off also. I got a new PSU 1200W and everything is working fine now.
Well, I do not have one specific out of service blade. It does not matter which 9 blades are inserted. But when I insert all 10 blades the miner turns off. I tested it with different cards which I put aside...
I honestly think that bitmain should have market this as a 0.9TH miner and have ONLY 9 boards plus BB in each. Sometimes I think that one hashing board is too close to BB and its heat might be affecting things. The tricky question is whether to put a board with heaviest or lightest heat sink near the BB. For me heaviest, strangely, worked the best so far.