While you wait for answers, we may have found some information which could help you.
Click here for Where Find Manual
tx 300 sporadic speed changes?
How can i fix my tx400 sportcraft treadmill model #04040?
Why does my Sportcraft Tx 4.9 run slowly?
Is there anywhere i can find a motor control board for my sportcraft tx4.9 ?
What can i do to fix it the number 3 show up?
Treadmill?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix gym/fitness equipment.