Randy suggested firing the X-ray Cathode and Anode slightly earlier. The previous delay time was set D=B-1.31us, in this condition the Rail Gap Anode firing was missed sometimes. When the firing time was moved forward, the Rail Gap firing became stable.
The Prometheus has been passivated for about 3 hours with the hight voltage of 10kV and DG 535 time delays of B=A-1.90us, D=A-1.45us. The red light was not changed anymore.