Today we combined the C-2154 circuit board and SCR together to check, we found pin 13 at C-2154 was not connected to common point. This caused the output of firing angle floating. After we fixed it, the firing angle pulse was changed. The test result was shown on the right picture, the wave 1 is the pulse without out common, wave 2 is the pulse after fixing.
Then I installed C-2154 and SCR back into the system for testing, unfortunately the high voltage could not be measured yet. The difference is that there was no high voltage output even after running for a couple of minutes. So we wanted to remove the C-2154 card to check again, however, we accidentally took off the card with the power on. We found the power was still on even I turn off the switch. Then we found the frequency-voltage converter AD-451L does not work, it must have been damaged when we removed the circuit board. I already ordered 451L from Newark. We will change the chip and fix the switch next Monday.