I have owned the Precor M9.55 treadmill for 6 plus years. I run on it 3-4 times per week approximately 6 miles. Recently I began having trouble with the control panel. After running 30-40 minutes, I could no longer change the speed, it seemed stuck. The treadmill would keep running, but I could no longer adjust the speed. The time before the last time I ran on it, this occurred at around 20 minutes of running, and the last time I ran on it, this occurred immediately. I have put in a call for a service call to check it out. Has anyone else had this problem and what did it take to fix it? The Precor M9.55 is a wonderful treadmill as far as comfort during running.