The belt catches when running. it is fine when walking. Vision Fitness T9250

Data Cable issue.

Large Data Cable Symptoms 1. E2 (T9200 & T9250 ONLY) 2. E5 3. E6 4. E9 5. No Elevation or speed function 6. No Elevation 7. No Speed 8. Deck goes to max at start 9. Run away speed Small Data Cable symptoms 1. No power to the upper board 2. Loss of power to the upper board, intermittent shutdown To troubleshoot a bad large data cable for most models - Enter engineering mode (see engineering mode for specific treadmill). If the elevation window in calibrations reads 000 in Px there no signal from the lower board to the upper console.
https://content.johnsonfit.com/inc/uploaded_media/4827226804f82ae5476352ddf9051547/troubleshooting_guide/87fc08ffe3e0caa8a9d3a1b15d59e71d.pdf

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First thing to do with these folding vision fitness treadmills is
REPLACE THE MAINS SUPPLY CABLE
They were supplied with very poor quality cable that cause issues like juddering stopping and speed fluctuations.

That sounds like a speed sensor. Make sure that the speed sensor is set properly and test it for continuity. If the sensor is set properly and functions then it's the motor controller, but that is unlikely. Also, if your model is over 9 years old and you've never replaced the walking belt then you should do that right away. If you don't you'll blow out your controller and then you're looking at a ~$700 repair.

Try to check the carbon brush of the motor. If it's OK then the motor control board would be faculty
If you wish to get some more details about treadmill repair then check the following link
http://electro-medical.blogspot.com/

Try to open and separate the motor carefully from treadmill chasis, turn the motor shaft with hand if it not easily turn or you hear a unsual sound try to open the motor and add a lubricant to motor bearing, and turn the motor on if its still noise replace all the bearings with new one

follow this steps and fix it. God bless you
This is probably a faulty speed sensor or the speed sensor is not plugged in properly. Its also possibly a faulty motor control board or lower board. The error codes will differ between makes and models but could be e1.
See the diagram attached.

will be better that you replace go to www.fitnessrepairparts.com and get it. or www.treadmilldoctor.com

God bless you

Dear Sir:

Please see the diagram attached from REED switch, adjust, clean, and tight the connector wires very well.

2) change the batteries by new ones, use the best.clean the contact batteries.

3) tight the ribbon cable from keypad .+ tight the connector from display board vs lower board.

4) after you fix it RUN THE sofware calibration for diagnose, troubleshooting, See my personal tips for help

sincerely. God bless you

It might just need a simple adjustment of the running belt that can eliminate the slipping refer to you owner's manual for the procedure. It will be close to all treadmill adjustments.
Here is a generic procedure for adjusting the belt:
If the walking belt slips when walked on. Run the treadmill @ 3 to 4 mph, walk for a few minutes, Using the allen wrench, turn both rear roller adjustment bolts clockwise, 1/4 of a turn. Then repeat adjusting procedure until walking belt is properly tightened.