We have a miller cp302 3 phase welder at work best welder we got. I got a little electrician experience and am in charge of fixing the welder when something goes wrong. A few weeks ago it started welding funny like it was at a way colder voltage than we had it set at. I checked the diodes and found one that was bad. We replaced it today put it back up welded nearly a whole bumper up and it went straight back to doing it again. I have an ideal multimeter with a diode tester mode I just wonder if it puts out enough current to really test diodes this big. I thought about using a test light and a battery this next time to test them, would this work?