You must be smarter than the welding machine.
My machine was making some very strange noises during AC TIG. The machine at school makes a nice constant buzz. My machine goes wOWowOWowOW.
I had the pulser turned off, EXCEPT... I turned the pulser off on DCEP, not AC. Apparently my machine remembers a different group of settings for each welding mode. I discovered that tonight and now my machine at home acts like my machine at school. YAY!