We received the 10k Ohm resistor this morning, then I installed it. In the afternoon I tried to passivate the system, it ran well until 4:30 pm. Then I heard clicks from the x-ray anode oil tank, the x-ray flux meter did not show any signal. I checked the reservoir and heater voltages for anode torturing, they were all fine. At the same time, the x-ray anode voltage monitor showed the high voltage could not reach 150 kV, it only went to 100 kV, then the voltage was dropped down to 50 kV (I heard the click from oil tank). This caused the x-ray gun running randomly, the system synchronization was failure. After checking the circuit drawing, I think there are three possible reasons to cause x-ray anode failure: 1) either SCR1 or SCR2 broken; 2) relay K1 control failed; 3) thyratron and its control unit not well. I plan to change the thyratron firstly tomorrow, then check SCR and relay K1.
The another bad news is the new Lecory oscilloscope is not working, so I could not save the waveforms.