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Topic: Treadmill Project (Read 23282 times) previous topic - next topic


Feb 18, 2014, 12:01 am Last Edit: Feb 18, 2014, 12:05 am by Rickmc3280 Reason: 1
    Got the Boards today

    Ran the Volt/Ohmeter on the pins and found that they are pushing 1 volt on all of the active pins.  
    * That makes me think that its possible all of the signals might be pwm.

    I bought the the 3.5 mm audio jacks, but none of them have come in.  I want to find a way to connect a wire to the wire being used and run the signal in my stereo/audio.  To do the oscilloscope trick.   At 1Volt, what is the risk of frying my audio circuits?  What I am hoping that I will find it the Square wave pattern going in speed but it also has 4 different speed labels on the boards.  Does anyone have any ideas on what the extra ones could be or how to diagnose it?  

    • SPD Up
    • SPD Down
      • SPD  - ST-IN (Maybe Start Switch In)
      • SPD - SPD

      Or any clue what the VR's might go to?

      I have contacted the company but they have yet to answer.


Feb 18, 2014, 03:56 am Last Edit: Feb 18, 2014, 04:09 am by dave-in-nj Reason: 1
typically VR-1,2 and 3 would be your 5 or 10k speed pot

just wire in a 10k pot.  
most time VR-2  will be the wiper.

as a note, treadmill controllers typically require that the speed pot be turned off or to minimum speed when the power is applied.  you cannot just start them as speed.

often there is a fixed ramp speed. so it will take x seconds to get to full speed.

looks like VR-1 is 5v and VR-3 is ground.
that means the wiper of your pot would go to VR-2 to control the speed.

very interested to know how that works out.

bty, if you motor has blue wires they are most likely to a temperature sensor.  they open the circuit when the motor gets too hot. 


figure the board is running about 120 to 140 volts AC
and 90 volts DC.

so, if you are concerned about your audio jack, select a resistor to start testing with based on those values.

figure your audio jack could handle about 0.1ma for your calculations.

better to start out too safe.

maybe even use an LED instead while you are getting things set up.


I repair fitness equipment for a living, so please allow me  pass on what I know. (which is not much).
During POST of the display pcb it sends an enable to the motor controller to activate the motor run relay but does not send a motor pwm signal. The controller reports to the display pcb the motor current and if it see a large amount the controller goes into "fold-back current limit". Fold-back current limit is done by the motor controller, but some display can do it also. This is to keep a shorted mosfet from throwing the user into the wall. So I would guess that one pin must be the relay enable signal. Also I would guess that the controller "talks" to the display.  I say this because some display pcb's allow me to view DC buss voltage, fold-back current status and RPM (better displays yield more info). I am sure that the RPM signal from the reed switch is passed through the motor controller and up to the display pcb. The lift motor is almost always controlled  by a simple "up" "down"  signal, but if the lift motor has a pot on it, that too will be passed up to the display. FYI, I work for both Spirit and Sole doing warranty repairs and they don't tell us anything either.
PS: Don't take anything I said as fact, just opinion.


Thank you for the info Dave and Jgum.

I have not updated lately because I have been trying to learn C++ and C# programming for the software side. 

I did try connecting a wire via exposing the speed wire and splicing it with resistance to the Audio in.  There was a lot of noise/interference to say the least and I did not see any form of a  square wave which leads me to think that the wire is the enable motor signal. 

Today I was doing research on building my own board, but Jgum, when you mention the Mosfet protection... that can be very important as these failsafes protect the user.  The last thing I want is a custom board breaking peoples backs, bones, and pride.

I still have not received my 3.5mm Jacks and I have avoided taking the jacks off of my beloved electronics, but I found an old CD Player that I might try to use.  Is there any particular way to set this up?  When I clip the wire using an alligator clip and run it to the 3.5 mm jack, is there anything that I need to do about the ground?  Considering that I would only have the 1 wire?

Dave, I would not know where to begin to calculating the right resistor size.  You are right, that it has about 120 Volts AC, but if i remember correctly, everything on the board becomes DC after the rectifier that we installed which is rated at 1000 Volts and 35amps.  (We installed it after troubleshooting the ohms on the board and found that the rectifier went bad). 

With Jgum's input would you still recommend installing a Potentiometer to try to control it?  I have not purchased one yet.  I was thinking about buying this (http://www.amazon.com/Digital-Potentiometer-ICs-Step-50kOhm/dp/B005T6CO86/ref=sr_1_5?ie=UTF8&qid=1392928695&sr=8-5&keywords=Digital+Potentiometer)  and then using my second Arduino to control it.

All of this info is still overwhelming, but i am trying to hang on in hopes of learning this stuff hands on.


put on a 5k pot.   a 1 watt or so.  the larger type on old radios.

if that does the speed, then just connect a stepper to the pot and control the stepper.

the irony would be that you are using a stepper to control a treadmill, that is, in a way, a stepper.


A pot will not control this board. When we test to see if a "NBM= No Belt Movement" is a mcb or display issue. We look for a .5 to 1.5 VDC signal. Our meters don't measure PWM, so this is a crude test to see if any type of signal is coming from the display PCB. We also listen for the relay click when starting the walk belt.


If a pot would not control the board, what exactly would you suggest?

If the MCB- board is not being controlled by PWM signals then I am not sure why when the treadmill starts the PWM LED becomes lit.  Starting to think building my own driver board would be best xD


The board is controlled by 0v to 5vdc square wave of variable period coming from the display. This is a signal that the ardurino can make, along with the relay enable ( a 5vdc High, I think) the drive motor should start.
I will try to find one of these boards in my stock and get a closer look.


Feb 28, 2014, 07:01 am Last Edit: Feb 28, 2014, 03:38 pm by Rickmc3280 Reason: 1
S/W - 17 Volt
Dwn - -.086volt
Up - -.086 volt
VCC - 18 Volt
Fast - 5 Volt
Slow 5 volt
Grnd - -.098 volt???
Spd - 5 Volt
Spd - 0 Volt
Vr1 - 5 Volt
Vr2 - 5 volt
Vr 3 - 0 Volt

Blew a few fuses trying to get amperage, because my multimeter has less than an amp tester.................. All the 5 volt ratings fluctuate some from 4.5 - 5.  Ill have to do more testing later.  The 1volt test was because I didnt test the Voltage on a high enough setting.  I am learning just how over my head this stuff is.  baby steps.

Actually, using Ohms Law, I should be able to check the resistance on the leads and calculate the Amperage since I now know the voltage right? A = V/R.


Mar 03, 2014, 10:07 pm Last Edit: Mar 03, 2014, 10:13 pm by Rickmc3280 Reason: 1
Latest update.

Got a 10000 ohm resistor tied in with a diode and am getting a 60 hz signal, but I cant really tell how to read the PWM yet.  


I have included the pictures of the schematics below.

I would greatly appreciate anyones assistance in figuring out how to use the Arduino to replicate this signal.

On JK1 there are 12 pins.  Of interest to me are pins 5&6 or Fast/Slow

in the picture Schematic 3   I have a close up of JK1 and the pins and their wiring.  Schematic 1 is the whole board.
Using Schematic 3 if you follow pins 5&6 it shows how it is connected.  In schematic 1 it shows another branch of it that I do not understand. I am assuming that signal goes to an IC

JK2 is the reed switch which I might also use later, most likely will need it for displaying speed.


Mar 04, 2014, 08:03 am Last Edit: Mar 04, 2014, 08:11 am by Rickmc3280 Reason: 1
After looking over the schematics for a few hours, I've run into the conclusion that there is probably more than just PWM signals being sent.  

PIC12F508 is a micro controller but I do know that  the signal from the GP2  goes to the opto which goes to the other Microcontroller (if it wasnt complicated enough).  The Fast pin goes to GP4, and Slow goes to GP5 and again everything coming out which is likely serial data of somekind goes out of GP2 which activates the PWM Led on the board which then goes to the Voltage IN on the ALT-633060A Microprocesor/controller which controls the PWM signal that goes to the transistors that control the motor.  So I either need to interpret the PWM out going to the motor, or interpret the data coming out of the GP2 from 12F508 which I imagine... I cannot do since I am a newb at all of this.

Any suggestions?  Anybody with 12F508 experience?  Anybody know how to interpret data from such a source maybe coming off of the opto?

I am going to be researching it a bit more.  

Here is the datasheet on the 12F508 - http://pdf.datasheetcatalog.com/datasheets2/16/1643295_1.pdf

(note: schematic says 12C508, but it is actually the 12F508)


looks like the whole speed control is two transistors and two mosfets controlled by one PWM signal.


Mar 04, 2014, 06:00 pm Last Edit: Mar 04, 2014, 06:02 pm by Rickmc3280 Reason: 1
Q3 Transisitor is NPN - BC637      http://www.onsemi.com/pub_link/Collateral/BC635-D.PDF
Q4 Transisitor is PNP -BC638      http://www.fairchildsemi.com/ds/BC/BC638.pdf or http://pdf.datasheetcatalog.com/datasheet/motorola/BC638.pdf

They  both have 60V collectors
NPN has +5 V    Emitter
PNP Has -5 V     Emitter

It looks like the Emitter for theBC638 PNP goes to ground so the NPN is isolating and amplifying the signal? The second one is smoothing it out?  I dont know anything about these things yet.

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