Treadmill locked at full speed

My treadmill (Proteus MTM 650) suddenly went to full speed and won't slow down.
The safety magnet does *not* make it stop.
Completely disconnecting the top board does *not* prevent it from keep running at full speed.
The switch on the bottom does turn it off. When switching it back on it immediately makes a bit of electric/sparks/static noise, and the motor goes to full speed.
I cannot see any visual damage on the top or bottom boards.
It is an old model, maybe 15 y/o, and has no programs. The incline is electric, but seems to be separated from the rest – it is only connected to a switch on the top board, that I also disconnected.
The only other link from the top board to the bottom is an Ethernet shaped connector.
What is wrong? Is it the motor controller? What is the controller? The entire bottom board?
Can it be fixed affordably?
Please do let me know if you need photos of anything. I will take it apart again and take them.

Thanks in advance for any assistance! :)


  • I forgot to add - when folded, laying on its side, open - the motor did not spin, but it did make some hum noise for a few seconds.
  • The top boards
  • By the motor:
  • Sounds like a motor controller went bad, we do not sell those parts or repairthose parts. Not sure of anyone who carries those parts.
  • Thank you for your help! – Does it mean the entire bottom board? Any idea what specific part of it?
  • You need to replace the entire motor controller.
  • here is a link that may help your get the parts you will need.
  • edited March 2016
    Thanks. I actually already submitted this form, but they haven't replied.
    I know you have no clue, but what would you guess would be the cost of such a board shipped?
  • Anywhere between $209.99 to $540.99
  • Seriously??? Are there manufacturers that actually allow repairing their treadmills? Or are they all the same in this regard?
  • You would need to contact manufacture for parts & service.
  • I understand. But if that would be the price, then I would like to know for my next purchase. Would ProForm, or someone else, be relatively cheap to repair?
  • depending on what proform you purchase the mcb can be between $99.99 up to $199.99
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