Hello. I recently got an older Solar 2127 wire feed mig welder. The question I have is can I reverse the polarity for flux core wire welding, and if so how?

I already had a look inside, still need to clean it out but didn't see any obvious places where you could switch wires for polarity. I'm assuming I would have to make my own leads and that this model wasn't meant for polarity switching.(I did find a post on here with the same topic but pictures describing a solution weren't hosted anymore)

Any ideas?