I have a used Lincoln Electric L3963-7 foot amptrol for sale. It's used, but still in pretty good condition. It has a five pin connector with pins 1-3 a 10k ohm pot and pins 4-5 a momentary ON/OFF switch. Pins 1-2 read 10k ohm when not pressed and when pressed down pins 1-2 read 0 ohms. Looks like someone had repaired the cable at some point, but everything checks out with the ohmmeter. I'm asking $40 plus a flat 10.00 shipping. If you have any questions, just let me know.

WVWELDER