The fix I had for cracking and popping of the arc on AC for AL, was a circuit board the company sent that I installed two days ago. The problem has not recurred and I am pleased there was a fix. The issue I had was no direction at all for the installation that turned out to be stone simply, but I had to intuitively figure it out. The fix was a reprogrammed board from what I was told. Although I don't know that circuit boards are programmed but manage the program in a CPU.