I have a Buck model 90 (or maybe a model 70?) I bought used from a friend in Sept.06. When I got it, the rheostat that controls the blower speed was physically damaged. I replaced it and the thermo-switch. The blower control worked great for about 3 months. I was able to regulate the speed from low (nice and quiet) to high (quite noisy) as needed. Suddenly, it would only run on high. Pulled the rheostat and found that one of the wire's insulation was cooked. Took it back to the distributor, they replaced it. Put the new one in; worked ok for part of a day, then it would only do high speed. As of yet, no melted insulation on the wires. Could it be a motor problem? The manual from Buck shows a seperate on/off switch for the model 90, mine is included in the rheostat. The distributor tells me the same rheostat goes into the 90 AND the 70. I am waiting to hear back from Buck; they're not usually real good with technical advise. I will take the rheostat to a nearby electronics store to be tested. Any input is greatly appreciated. Thanks. Gary