Changing electronic control treadmill to manual control

[Mike Maggiacomo]

Hi,

I have a Reebok treadmill where the touch controls are not operative (and the replacement console is not available). I would like to see if I can hook it up with manual controls, one dial for speed and one for incline (bypassing the electronic controls). I don't imagine this is impossible, but I would require some help on how to do it!

Any help you can give would be appreciated!

Thanks,

Mike M.

 

[crutschow]

The motor is likely a 100VDC motor of about 1HP or so which would require a PWM circuit to control the speed. Controls for that voltage and power are not simple to build or cheap to buy. Look at this for some info. Unfortunately most of the modules you can buy are designed for 30V maximum or so.

The incline adjustment should just require a DPDT center-off switch to turn the motor on or off and change polarity to control the direction..

 

[Mike Maggiacomo]

Hi Crutschow,

I believe it is more like a 2HP motor. It has a motor control board already, isn't it possible to use that as the basis for controlling the motor manually?

Thanks,

Mike M.

 

[iamsuperbleeder]

might be hard to say without some sort of schematic for the existing control board

 

[Mike Maggiacomo]

True, true! Maybe I will get lucky and find that somewhere!

Thanks,

Mike M.

 

[3v0]

Have you googled for places that repair and sell replacement boards ?

 

[Mike Maggiacomo]

Hi 3V0,

Yes, I found the console at "Treadmill Doctor", but the last time I enquired it was not available. That may be different now, but at $399 for the console I am still hoping to find a cheaper way to get it running!

I found a basic troubleshooting schematic for the unit (attached) and was able to confirm some operations. All the voltages from the console to the motor control board seem to be 0-5 volts. Using a 1.5 volt battery I was able to jumper the incline pins and get the motor to work. Using the same battery I attempted to jumper the main motor pins (the schematic says "BLUE PWM 0-5 Volts" but also says "digital multimeters may have a problem reading the voltage and may only read a maximum of 1.5 Volts") When I jumpered the pins using the battery, the main motor sometimes attempted to turn for a short time (.25 to 1 sec), but not under constant application of voltage to the pins! It seemed to work sporatically when there was a loose conection or when I deliberately wiggled the wire to pulse the conection! Does that mean there is some sort of PWM circuit in the console that pulses 0-5 Volts to the motor control board to run the motor? I am assuming that pulsing 1 Volt will cause a set speed, while pulsing 2 Volts will increase the speed (and so on).

This is very interesting, and I hope I can get it to work!

Thanks,

Mike M.

 

[3v0]

PWM Pulse Width Modulation has a fixed frequency/period. In this case the speed of the motor is determined by On to Off time ratio.

I am guessing that when you touch the wire there you have a condition similar to switch bounce where the power is on and off several time with one touch. To the motor controller this looks enough like a PWM signal to start the motor.

Maybe setup a 555 and try a real PWM signal on that pin.

You did not say what model number the threadmill was.

Give J&R tech services a call. They claim to do actual repair.

 

[Mike Maggiacomo]

Hi 3v0,

That make sense. I am unfamiliar with 555 circuits, can you point me to a tutorial on setting up a suitable circuit for this use? How would I determine the correct frequency?

It is a Reebok 3500C, but the motor control board is an MC-2100 part number.

Thanks for the info!

Mike M.

 

[Mike Maggiacomo]

I took apart a couple of battery powered drills to try and use their PWM module, but it did not work. I am speculating that the frequency was too low, but that is just a guess!

Mike M.

 

[3v0]

There must be a load of 555 tutorials on the web.

ThreadMillDoctor has the motor control board for $150. But I was thinking it was your console that was bad.

 

[Mike Maggiacomo]

Hi 3v0,

Yes, the console or overlay, is definitely bad. I bought an "Arduino" board to play with PWM signals, and I applied 500hz, 1000hz, and 31000hz to the PWM pin on the motor control board with the same results as before (motor starts for less than a second only when there is a "loose" connection). I also tried two cordless drill PWM units with the same results. I would think that the application of a valid PWM signal would just work! The LED on the motor control board flickers when I get the motor to start, which indicates a valid speed signal, but, of course, it doesn't stay running!

Thanks for your thoughts!

Mike M.

 

[crutschow]

Have you just tried applying a DC voltage, varying slowly between 0-5V, to the PWM input?

 

[Mike Maggiacomo]

Hi crutschow,

I tried using a 1.5 volt battery and 5 volts from a power supply (and got it to start sporatically for less than an second when there was an intermittent connection, but no go.

Mike M.

 

[bobledoux]

The controllers for treadmills have a slow start and slow stop routine. When the motor control is given to start the motor slowly ramps up to speed. I used a controller to operate a treadmill motor on a lathe. It was controlled by voltage divider pot. The voltage always had to be turned to zero volts before the motor could be made to run.

 

[Mike Maggiacomo]

Hi bobledoux,

Roger that about the slow start! But, wouldn't the voltage be at zero before I apply the PWM pulse to the pin? One question I have is, does the MC-2100 expect a pretty exact frequency, or is there a wide latitude the controller will accept? I have been unable to determine the frequency of the 2100 board, but I thought it was around 20k or so?

Thanks,

Mike M.

 

[egai]

treadmill manual convertion

Hello!
I have a treadmill which has a defective battery operated plc panel control,I want to convert this manually by using the existing rheostat on the panel.my idea is to modify the pcb so that the output could produce 220volt d.c.and be able to control the speed of the permanent magnet motor by controlling the frequency by using the rheostat?.Could it be posibble to make some modification on the pcb,?forexample to put some bypass circuoits?Do you have a schematic diagram of this kind?

 

[egai]

treadmill manual convertion

Hello!
I have a treadmill which has a defective battery operated plc panel control,I want to convert this manually by using the existing rheostat on the panel.my idea is to modify the pcb so that the output could produce 220volt d.c.and be able to control the speed of the permanent magnet motor by controlling the frequency by using the rheostat?.Could it be posibble to make some modification on the pcb,?forexample to put some bypass circuoits?Do you have a schematic diagram of this kind?
thanks. egai

 

[second286]

For Mike Maggiacomo:

If you have the incline motor working; then I would perhaps take a look at a simple method of controlling the drive motor with an appropriate 120 Vac Variac. Simply rectify the variable 0 to 120 Vac output with diodes. Which would connect to your "CB1" and "CB1A" inputs of your Drive Motor.

Vdc=2*Vp/3.14=2*170/3.14=108 Vdc; the 170 Volts peak is 120 Vrms max out of the Variac ( or 105 Vrms for 95 Vdc).

The turning radius of the Variac would need to be mechanically limited to allow no more than a 95 Vdc output; as stated on your schematic-or even less if the household AC current exceeds 15 Amps at full motor speed and load. The specs for the diode current rating and PIV must be calculated. Everything is easily found on the net. As with any circuit built to run off household AC-an appropriate circuit breaker or fuse should be installed between your power cord and Variac.

 

[OlPhart]

I've done 2 of these for the same reason: replacement of which/both defective part(s) is unavailable/too expensive.

As crutschow: elevation motor is reversable AC, just 1 neutral & 2 line/hot, an SPDT works fine.

Belt driver is PWM thru MOSFET drivers (see MCP1406, etc) to MOSFETs. I used a Freescale 9S08QD2, the code is SO simple I enclosed it. It always starts at zero speed, ramps up at a reasonable rate & shuts down on the safety magnet switch going open.

Just use enough drivers, transistors, heatsink & fan. You can't easily build it too big. Good Hunting... <<<)))

P.S. ignore the copyright, it's my business name... I wrote this code - just don't use it for profit