Good day everyone, I have a Inverter IGBT welding machine here with 4 -1MBH50D-060S. Before the 4-IGBT are blown including rectifier which is GBPC 5008. I finish replaced all 4- Transistors and rectifier diode. After I powering my machine, power is good without a light of error indicator, but when I touch the torch to the ground the transistors are blown again. Any recommendations to check parts is appreciated!