Help needed Cutmaster 100

[Broncoxpl]

Hello everyone. I'm new to your forum and I need help/advise. I just purchased a Cutmaster 100 used in not working condition. When I got it home I opened it up and found that both IGBT's were blown. So I purchased one from a repair facility ($200). I found a new IGBT module and ordered it in and unsoldered the old one and installed the new one. Theoritically speaking this unit should work. So I think. 1st I plug in machine. (So far so good). 2ndi hook up air compressor (still looking good). 3rd turn on machine and it powers up. Power light flashes for 8 seconds then the contactor switches on. 4th I flip the run/set switch to set and adjust my air pressure to 70 psi. Everything still good to this point. So I flip it back to run, air shuts off. Unit should be ready to go. 5th I pull the trigger. Ac and gas lights are on NO DC light tho. No pilot arc nothing. And I hear a pop. CRAP . I opened the machine back up only to find it had popped both IGBT's again. I'm guessing this was the original problem before I got it. Any ideals on what could be causing the IGBT's as soon as the trigger is pulled ? Any help would be greatly appreciated. Not sure if this machine is worth the money to fix or not.

[adbuch]

There may be a short circuit/over current condition causing those transistors to blow. I would check the schematic (if available) to try to figure out how to trouble shoot the circuit.
David

[Broncoxpl]

Ok thanks I have the schematic but can't seem to figure it out was hoping that someone might have had this same issue at some point.

[italogarcia]

Probally is short circuit in the primary or secondary terminals in the chopper transformer