I found this super helpful write up all about plasma cutters. https://plasmacutteradvisor.com/plas...oubleshooting/
I was was actually just about to buy a new plasma cutter to replace my Lotos Lt5000D. It had been acting up about 2 years ago and I could NOT figure out what the problem was. I said F it after getting frustrated and avoided messing with it for a couple years. I figured I would have to buy a new plasma cutter and told myself to not buy a Chinese machine again. I could not wait any longer, so back to the internet one more time before spending my saved money on an American made plasma cutter.. The problem to fix it was so simple, the machine has a set of points inside that need to be set accurately! The Lotos cuts great now. So I had to pass on the site just in case your in the same boat as I was. Remember to measure twice!