Sounds like the magnet pulley wheel is broken....I've been trying to find this part, and I'm not having any luck. This part is located on the front roller. Take the cover off, and if you are standing on the treadmill, there's a black round plastic piece on the far right which fits inside the U shaped plate. Mine is broken. Hopefully yours is not broken too. Search the internet for "TX 5.0RC Treadmill Trouble Shooting:Speed Sensor and Step Count" and follow steps 1-3. Hope this helps.
KT, February 2009
