ProForm 1200 ZLT - belt randomly runs slow

Hi, I have recently bought a cheap second-hand ProForm 1200 ZLT treadmill. It doesn't appear to have been very well looked after but I have tightened up the running belt and hoped that it would suit my needs. I am now getting an issue with it where randomly the belt will run at a very low speed regardless of the speed setting I have set and when I stand on the belt it stops. As mentioned I have tightened the running belt and I have checked the drive belt which does not appear to be loose or slipping. Does anyone have any ideas on what the issue might be and am I able to salvage the machine?

Here is a video of the issue -

Here are some videos of when the machine is running normally at various speeds:


  • this is most likely a failed motor controller and from video fsx2up, the belt sounds as if its too tight. I would also replace that belt.
  • Thanks KevinC, is it possible to replace the motor controller with a generic replacement? It seems to be difficult to source parts for my exact model as it's obscure.
  • Can you get me the specific model number of the 1200?
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