Our older Syncrowave 200 (manufactured around 2006 or so) recently started producing grainy, over-penetrated welds on steel and large, grainy-ish beads on aluminum. I've done a search and feel I am getting closer to figuring this out (maybe a high frequency start issue?), but still need help. Notes of our experiments are below and any help would be VERY appreciated.

1. Not a gas issue as far as we can tell. We have checked all lines, tried different cups, and the same bottle will produce both grainy and normal welds (intermittent).
2. For what it is worth, we were doing one of many test samples on steel when...one bead...halfway through the bead, a small shock went through the guy's hand that was holding the rod. The bead instantly turned from grainy to shiny and perfect. You can see an exact line where this happened.
3. We've had the same machine and the same two people using it for the last 8 years.
4. If we put the torch over an ungrounded scrap and hit the pedal, it'll only spark about 40% of the time. Even if the arc doesn't form at the torch, the spark gaps are sparking (not sure if this means anything)
5. We did check the spark gaps. They are clean and gapped to .008. They have a clean spark when the pedal is hit.
6. The machine was cleaned out. It was dusty. Not anymore.
7. The fan isn't working. We have a part on the way to fix it, but I'm wondering if something inside got fried after the fan went out.
8. The resistor that is oriented vertically is browned. It gets to about 500 degrees.
9. After chasing the issue all day yesterday, we kept getting beautiful welds the last 15 minutes of the day. We were convinced the problem was fixed, then today it was the same old graininess.
10. We took apart the clamp and cable, cleaned them, and reassembled.
11. We didn't really notice the problem on steel until one of our guys had to weld a bunch of aluminum.
12. We tried 2 different pedals. Same problem with both.
13. We opened it up and looked for unwanted arcing and didn't see any.
14. We held all four buttons on startup to reset the machine.

I'm tearing my hair out over this. We are pretty certain it is an electrical issue. If we can get the right parts, my electrical guy can probably get it sorted out...we are just having a difficult time figuring out which parts are faulty. I afraid what kind of bill and service I'd get if I took it to a repair facility.

Thanks for any help!

Nick