I've been practicing my tig welds with the DX200. Runs flawlessly! However the other day I noticed something weird. I have the amps set to 120, the frequency at 50, ratio at 75% and the balance at 50. Using the foot pedal. As I'm welding I noticed the arc getting smaller. When I quickly checked the amps it had dropped to 18 amps. I thought that maybe it was a bad ground so I reattached my ground cable closer to the weld area but no change. Anyone else have this issue? Am I missing something?

Thanks...