This morning my sprotcraft TX400 treadmill worked for 6seconds. I put in all the settings and it started working but stopped after 6 seconds. The panel went blank except for the calorie counter which had the number 3 displayed. It kept happening after several tries.

Brian Smithers, April 2008

The speed sensor could be dirty. Remove the hood and vacuum any dirt you see. Then try to blow it out. Look for strobed plastic wheels.
Your speed sensor reads of of these.
I have a video on treadmill maintenance that can show you how..
http://www.mindbites.com/person/214-Mark

Mark Peterson, April 2008