Broken PowerPro 256

[86k5heavy]

I have a PP 256 that I was using to plasma and the arc went away so i pushed the

button again and I heard a pop from the left side. Then the unit stayed on but the arc

wouldnt come back.

I have pictures of what popped. My question is what went wrong and how can I fix this?

I can solder in a new piece if necessary.