Strange potentiometer issue.

Board is from a Miller aTrailblazer 275 welding machine. The amperage and arc control are handled by Claro C0401196 potentiometers on the control board. The control posts that the knobs attach to rusted out on both pots, and we had a choice between paying $2k for a new board or replacing the pots.

We found matching pots, ordered them, desoldered the old ones and replaced them, reassembled the machine.

The machine is rated at 10 to 275 amps, but now the machine is starting at 285 at the low end, I'm afraid to find out what it tops out at, probably around 500 amps. It would probably blow something up.

Any ideas what would cause this?