We had similar issues with our new challenger three years ago...would not stay in upright locked position, would not oscillate correctly...

I had bought recently a "fix" to the upright position problem, cost about $180 w shipping. Didn't help much. I have a sneaking suspicion that there had to be damage during shipping that did something, as most folks are more than pleased with the machine.

As for the oscillation, our drive shaft snapped two weeks ago, again I think there was a problem during shipping years ago, as most have had no issues.

I have always found the Watsons at Challenger Pad Systems eager to try and assist any Challenger owner with technical problems of this or any sort. I suggest that each of you e-mail Chris and Lee Watson at
challengerop@gmail.com and individually describe your problem, whether or not your machine is still within the warranty period. I will also e-mail Chris and suggest that they take a look at your posts.