Miller Trailblazer 44G help.

[PRR]

I have an 1985 Trailblazer 44G serial #JF850xxx. It’s been sitting in the elements for the past 15 years. I spent the past few weeks looking it over and getting the engine running. The generator works to power a grinder with no issues. I fear I have messed it up! In my haste to try it out I hooked the ground clamp to the electrode and vise versa. It “welded” for about 1/2 a rod and then stopped and will not strike an arc now. Before I figured out what I had done I tried the 110v outlet and it worked. Then I shut it down and started looking it over and noticed my screw up. Had it set to about 10% on 100-55 amp setting. After shutting it down I took all the covers off and looked it over. Don’t see any burnt components or smell anything burnt either. Upon doing this noticed that several of the ceramic capacitor are brittle and the lead on C10 was broken as well as C16 or C17 was broken as well the are around the remote contact. I am familiar with circuits and troubleshooting. At this point I am looking for a place to start. I figure checking the windings resistance, visual inspection of the stator and brushes to make sure the generator is not ruined. I have access to a megger through work. I have found most of the ceramic capacitors I need through Newark or Mouser.

Thanks,

Scott

[Oldiron2]

As you might guess, I don't know that machine at all. However...
Whereas some electrodes or situations require running them "straight" polarity (electrode -), even though most get run "reverse", any good DC machine should be able to handle both without problem. If only AC, I believe it also shouldn't matter. More likely, dried-out electrolytic capacitors, unseen corrosion or some other problem is causing it not to arc. What produces the current, a generator or an alternator? Could brushes be stuck open on it? Any fuses or circuit breakers?
Are you sure you even have a problems? What rod type were you using? Some electrodes have a flux coating that will cover and insulate the end, once the arc stops. It needs to be ground or chipped off to allow restarting a new arc, often done by tapping the rod on the workpiece.

If there is a real problem, I'd suggest trying to get the proper schematic for that machine and then starting by checking all the important contact points. Posting the schematic here also might be useful. Hard to make specific suggestions when I don't know any details.