Even while on manual setting the speed automatically goes up and down, how can i fix this? For instance, I set the speed to 2 and it jumps up to 4.2 for a few seconds, goes down to 1.9, back up to 3.xx, etc, and finally settles somewhere around 2ish. The product is Proform Crosswalk Advanced 525x, but that was not a selectable option in your drop down list.

1. You may have a belt and deck problem. Test by the following procedure: a) without the power on stand on the walking belt b) push the belt in the direction it normally turns c) if the belt is very difficult to turn (on most treadmill) this means that you have high belt/deck friction these parts will probably need replacement. On occasion, you may have already damaged the DC board if you have high belt/deck friction. If the belt walks freely, you have a different problem. 2. If it passes the belt/deck checks, you may have a DC board output problem. If the belt tests ok and you have a speed variation, try this test: a) Set the speed to 2.5 MPH. Let the treadmill run without anyone on the belt. Check to see if the speed is constant or if there is a variation. b) If there is no variation, step on the belt. If the speed slows down or speeds up, you may have an output problem on the DC board. This is the board that connects directly to the motor. 3. You may have a short in the motor. If you turn the machine on and have erratic speed, you could have a problem in the DC board or the motor or both. With a simple multi-meter, you can test on the continuity scale to see if you have a closed circuit between either DC motor lead and the common earth ground. You should always have an open circuit. 4. You may have a speed signal problem. Your controls on the upper panel send a signal to the lower electronics to help them set the appropriate speed. If there is a problem in the signal generator, the communication links, or in the feedback links, you will have erratic speed operation. a) Communications test- Look on the board for a flashing signal as you increase speed on the treadmill. Most boards have a signal feedback test light. If a LED flashes, your communication is ok. b) Feedback test- If your unit is equipped with an optical feedback (disk inside a sensor) you can swap the feedback unit with the incline (it is the same part on many Icon machines). If it tests ok, you don’t have a problem here. If it is a magnetic feedback unit, you can test continuity with a multi meter or replace with a new part to test. Many times passing a kitchen magnet in front of the signal will make a speed display on the console if the magnetic sensor is good.

I have a Proform 625 that was doing the same thing. It was a speed calibration issue. When I ran the calibration, the max speed went to 11.7mph - it was only supposed to be 10mph. All it took to fix was running the calibration and using a Phillips head screwdriver to turn a little yellow screw on the side board under the cover. Directions for calibration were taped under the cover or you can find calibration directions for Proforms online.