Welding Tips and Tricks

Good morning all,
I have an MLS 2300 ACDC TIG. I am currently facing a problem that I can not flick on the option DC-
Every time I try to choose DC- option machine skip that and jumps to the next one.
Has any one faced similar issues? Any suggestions.

I'm not familiar with the machine. I'm assuming that you use the arrow buttons to select the mode. Have you tried going the other direction with the button? Can you feel if the button is sticking while selecting? Have you contacted the manufacturer about the issue?