The possible reasons are:
1, the fuse broken, can cause the whole machine no electricity. Performance, according to the control panel without machine.
2, line pressure is broken, usually will appear in the process of the new machine installation problems. Performance: the new machine can't work properly from the start.
3, the control circuit board is out of question, the machine use for more than 1 year, long overworked, or be affected with damp be affected or don't start for a long time can cause. 
4, the control circuit board is out of question, the machine panel damaged by weight or buttons. Performance control panel display or mediation is not normal.
 Suggestion:

find the original manufacturer warranty period after-sales maintenance, warranty period parts out of the question is what they provided free of charge. If is out of the warranty, Contact the local treadmill dealer or maintenance service provider to check and repair.

Possible reasons:

 1. Check the roller for damage or not.
 2. check whether the motor carbon brush wear uneven.

 3. Check whether fender retaining screw loose.

 4. The belt wheel touches the speed sensor.
 5. Running belt run into the lining eyewinker.
Solution

  1.Replacing drum.

 2. Replace Carbon Brush.

 3.The fixed screw.

 4. The dispatch speed sensors to appropriate location;

 5. Remove debris

Possible reasons:

 1. check whether the safety switch is played or not on the electronic watch;

 2.The connection line is not completed.
Solution:

1. Press the safety switch.

2. connect the line replace the electronic watch.