So i have TIG/MMA welder branded as ROHR. And the last time i used it it had lost amperage and itstarted smoking from the vents. so straight away switched it off and opened it up to find nothing. mosfets all seem to be intact and ive tested them all. now with the machine on i dont get any amp reading on the display. Gas doesnt kick in when i run the torch, neither does the HF start. does anyone have any other suggestions to look at? thanks