Quote Originally Posted by mts211si View Post
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The stick function doesn't work when cold either. I let the unit sit for a few hours and tried to strike an arc with the stick function, but nothing. Warmed up the circuit boards similar to before until the drive roller started spinning when torch button was pressed. At that point I could switch modes and stick weld. I believe this means that the cold solder joint (or whatever the source of the issue is) affects more than just the feed motor. Note: the display, gas solenoids and fan all work when cold and don't seem to be affected.
Sounds like a thermal issue for sure. Since the stick function is also out it is probably deeper in the circuit than the drive output. Look over the board with a magnifier or microscope. Look for poor joints, cracked traces, or lifted pads. Reflow anything suspect. Also this could be a thermal issue inside a component. Check any socketed components for bent pins and being fully seated. Because of safety issues, I'm hesitant to go any farther. But if you know anything about tracking down intermittent thermal problems in electronics, you can probably track this down with standard procedures. These are high energy circuits so if in doubt, send it in for repair. If you touch the wrong thing, it can and will kill you, before you can say whoops.