Yesterday in Welding Class, I was demonstrating my favorite machine in the shop - the Dynasty 350. Right after showing some aluminum welding, the machine powered down, as if someone had shut off the power source. No tripped breaker, input power cable checks out okay. What should I look at next? This machine is 2-3 years old, when I get to school, I'll post the serial number if that would help figure out this problem. Thanks