That's an interesting manual. I see these machines not only have the 'overheating light', but also the 'Abnormal phenomenon' light as well.
Really advanced stuff, eh?
On my set isnt like that one its a DC only set. I have a 3 position toggle switch and a knob on the top right of the front face. The switch has a straight line P1, a narrow square sign wave P2 and a wide square wave P3. What are they and what do these do?
I had a look at for the manuel and I could not find it, I will have a look at my welder tomorrow as you have the same one as me. Had a few beers so not thinking straight but think the switch your on about is a pulse switch.
Had a quick look, the switch is for pulse mode and the dial on the right is the intervals for this, only played with it when I first had the welder but I just leave it on the solid line setting.
For me I need to follow one simple step KISS (Keep It Simple Stupid)