Tread lightly.

Last week I was using my treadmill when the motor unexpectedly stopped.   In the days since then, I have learned more than I ever wanted to know about the inner workings of my treadmill (a 12 year old, well-loved Schwinn 845P).

The important bits under the cover include the digital display console, a hydraulic incline motor, a DC motor that drives the belt, a sensor that measures the speed at which the treadmill’s belt is turning, and an electronic board that controls all these things.

The symptom:  The motor and belt just stopped abruptly during a workout.    The console still works.  The incline motor works as well.   Any time I subsequently turn the treadmill back on, the console lights up, prompting for the usual inputs.  Then when I press the start button, I hear a “click” after which the motor used to start-up, but now doesn’t.  And after a few seconds the console just displays the message “Err LS” (looks also like “Err L5”) which apparently stands for Loss of Speed, which is an error message related to a number of different failures.   I had to figure out which component had failed, causing that error.

Disclaimer:  I am in no way suggesting you do this at home yourself.   I’m not an expert. 

The patient:

The diagnostic process in my case:

• No belt movement at all.
• The circuit breaker next to the power switch has not tripped.  And, besides, electricity is able to power the console and the incline motor.
• None of the capacitors on the control board appeared to be swollen or visibly failed.
• All of the wire harnesses and leads seemed to be seated firmly – no loose connections that I could see.
• The fuse on the motor control board is not blown.
• If I move the belt with my hand, I can see the “SPEED” led on the control board flashing as it turns, meaning the speed sensor is not the problem in my case.  It appears to be working and sending a signal to the control board, which is receiving it and flashing the LED as the magnet on the drum passes the speed sensor.
• I disconnected the (DC) motor (P/N KK 2566) power leads from the control board and hooked them up to the terminals of a 12V car battery to test it by itself, and the motor worked fine.  An inspection of the brushes also showed them to be in good shape.  The motor is just not apparantly getting power from the control board as it should be.
• I can hear the relay click after pressing the start button, but the board is just not sending power to the motor, or at least not the right amount of power.   A multimeter showed 3 Volts coming from the board to the DC motor.
• I googled “Err LS” and “treadmill” and read as much as I could find.  There are alot of problems that can cause an Err LS message.  I
• I called Schwinn to got their take, and even though the treadmill is out of production, I experienced great customer service from Joseph as he talked me through things to check to narrow down the problem.

The consensus diagnosis:   Through process of elimination, the problem appears to be a failed control board (motor control board, actually).   Apparantly this is a very common failure on treadmills of all makes and models.

The fix:  I found a website called FitnessBoardsDirect, that carries such things.  The replacement for my motor control board (P/N QQ 2197) is a new-from-the-manufacturer item, not a refurbished one.   I called them as well.   A guy named Nick answered the phone and was very nice and helpful;  he confirmed the diagnosis and gave me a little more confidence that the item I would order might actually fix my problem.  So, I decided to shell out $225 plus shipping for a replacement motor control board.   Not cheap, but much less expensive than a new treadmill – a comparable new model retails for $800-$1000, depending on who you buy it from.

My replacement board arrived tonight and I installed it, and it worked.  I’m back in business!   🙂