Judgeless,
Many of your answers are non answers...Regarding the 2T function with the torch, this is a non answer. I didn't ask you how you "assumed" or "expected" it worked. I asked you to verify that it DID work. You make too many assumptions...either that or your reading comprehension and problem solving skills are way off the norm. I don't mean to make fun of that if they are, but several people have pm'd me about that very possibility on your behalf. The way this works, if you have a problem, I ask the questions, you answer them as fully as you can without extraneous information or opinion, and then I come up with a possible solution...THEN and only then, if you have questions ask them... Asking them in the middle of a diagnosis process does not do anything but hamper the process.
So you understand, as an Electrical Engineer, who would normally be thought to be routinely involved in problem solving....You asked me if it was the torch or the unit to begin with. How do I know? Take a WAG? No, I ask you a series of questions that will define how the unit/torch is behaving. Intrinsic to this particular question is determining if the torch is working in 2T with the amp control. If it does not then the probability is increased that it is the torch.
Also I asked you to determine what you see with your eyes from the arc. Whether or not it displays on the unit is immaterial as to whether or not the unit is functioning by increasing and decreasing the amps. I asked you to use a real live test and tell me what you see, not something where you are staring a display. A display may or may not be linked to what is happening at the arc. I never (and no one I know of) looks at the display while welding to determine if they are getting any change in heat or the arc. The display is for bystanders in this situation. If the amps change fine, but that doesn't even mean the arc is putting out anything or changing up or down...and vice versa...especially since it's a moot point while involved in the actual weld process. On most units it does change to read actual output, but I've never had reason to verify if this unit does or not. Perhaps later today, I'll get a chance to check to see if it does. If it welds, and changes regardless of what the display does dynamically or statically, I'm good and so would a lot of other people be fine with it.
The reason you have the background menu is to alter the way the unit works with 2T/4T control for different types of controls as I have told you before. With an amp control that has the switch built into the travel action, where no separate switch is needed, a basic 2T is all that is needed. It's because you roll the amps and the switch is linked to the mechanical action of the unit, whether it's a foot pedal or a CK rotary or slider switch. 4T function will not work this type of control, so 4T is disabled in the normal mode that would be used for a foot pedal or a similar operating amptrol torch.