I'm pretty sure I fried all the diodes when I plugged my brand new Lincoln 140 into a shop that had the hot and neutral reversed on all it's outlets, with no ground. That was 12 or so years ago, and it's been collecting dust ever since because it never has welded right. Won't penetrate or puddle. So now I'd like to find the diodes so I can test them, and replace them if need be. Has anybody out there ever torn into one and done this on their's? I've got the cover off but cant see any diodes. I'm about to start unbolting the plate on the left, behind the spool. But it looks like maybe the black plastic on top of that left portion has to come off first. Any help would be much appreciated