Lincoln Idealarc 250 polarity switch issues.

[493mike]

Hi fellas,
Yesterday I started welding and noticed the polarity was incorrect. I reached down and flipped the switch up to reverse DC from the AC position and sparks flew in the back of the machine. The tag at the switch says to NOT move under load and I didn't. The power was on don't recall this being a problem in the past. What did I do wrong?
I shut off the power, switched to the position I required, and turned the power back on and all was well?
Mike

 

[sberry]

It might be broke.

 

[American Locomotive]

The polarity switch may be failing, and might have possibly shorted the output together.