I’m 99% the Cutmaster 50 is not a HF start. It uses a pilot arc to initiate the plasma stream(see page A2 in the appendix). You can also look at the torch and tell if it’s HF or blow back pilot arc start. Remove the shield cup and see if the tip is spring loaded or fixed. If it’s spring loaded then it’s pilot arc. There should be a starter cartridge under the tip also which has the spring inside.