Radio Shack carries high wattage fixed resistors, I used those when I first got my tornado and made a switch from them so I could run it at high, med, slow. They carry 8 Ohm fixed power resistors. You wire 2 of those to a switch so the run in parrallel and series. In series your running 8 Ohms for slow speed, parrallel your running 4 Ohms Med speed and no resistor for full. That worked fine, until I found that Rheostat. I bought 2 of them and well worth the 3 bucks or so. Are you sure you wired the rheostat right? Usually when a Rheostat or pot burns out you lose a connection because the resistive element burns up, but thats all that happens. Like I said its the same Rheostat they are selling for 12 dollars.