Thank you for allowing me to assist you, my name is Joe and I will be happy to assist you with your concern today.
I would start by bench testing the motor, it may be weak or the track/belt sticking. It may also be related to the display, you will need to use a voltmeter and check power/ground to the display to see if the control board needs to be replaced.
I am just seeing if you still need assistance with this problem? The reason I ask is because I see that your question has not been answered sooner and I wanted to make sure if you still needed help.
In some cases a question may sit due to several different things including the amount of the deposit/question value, time it was asked, the complexity of the question, number of experts that can help you at a certain time, lack of detailed info and so on. My objective that I wish is to make sure that if you still need help that I can at the very least reach out to you and attempt to help you.
At this time please feel free when you are ready to reply back to me and ask to continue working with me, another expert or if you no longer need help please just let me know exactly what you wish to do.