How can I make this treadmill motor controller just a simple controller with a potentiometer?

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
I have a johnson fitness JDYF02L controller board and a johnson 2.25 hp dc90v motor out of a horizon cst4.6 treadmill. I am trying to find a way to control the motor with the controller board somehow so i can mount it onto my milling machine and have variable speed. I have found info of it being done on many other types of controllers just by wiring in a potentiometer to a G O H or L W H marked terminal but this board does not have those that are clearly marked. Please help
 

MaxHeadRoom

Joined Jul 18, 2013
18,863
Is there a part No on the board is it JDYF02L the only number?
Most have a pot input but some have a an exception and are PWM control signal input.
Or post a pic of the motor board.
Max.
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
There is some numbers on the heatsink JC07-001 SJED08089IF VER:H109 JC07MC0608AA06947. I will try to post some pictures as soon as i figure out how. I do know that in the main harness coming from the original dash it has a PWM terminal. Thank you for the help
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
Ya i did alot of searching and could not find any schematic on this board. I need to learn how to reverse engineer this thing then I guess.
 

MaxHeadRoom

Joined Jul 18, 2013
18,863
In the absence of anything useful it may the only way to reverse engineer, I think I would start at the drive mosfets, I am guessing it is PWM output, and work back from there rather than the input connectors.
Max.
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
Ive kind of narrowed it down to the 8,9,10th pins that "I think" go to the main motor which are +15v/VOD, speed command power/PWM, RELAY/MOTOR. I have atleast ruled out the other pins. Can someone please tell me what i need to do to make this work? And could someone also tell me what kind of power i should have on the positive and negative side of the MP3508w 35A bridge rectifier?
 

MaxHeadRoom

Joined Jul 18, 2013
18,863
If it is a PWM controller you will have around 165vdc on the output of the bridge for a 120v AC in.
Max.
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
I found another number on the board that i overlooked! WJ28041T I hope this helps, im still struggling with this thing!
 

MaxHeadRoom

Joined Jul 18, 2013
18,863
Well at least that appears to be The valid number but no luck anything showing up so far.
Where does the pin marked PWM go to?
Max.
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
I have zero ohms between the pwm pin and the gate pin of the IRFP260N mosfet. I jumped the main power relay because i cant figure out what turns it on and i get 165vdc to the pos and neg motor pins. How do i switch this mosfet?
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
Wait i was wrong, I forgot i dismounted a resistor that was mounted next to the mosfet in that circuit.
 

Thread Starter

Ironworker613

Joined Jan 20, 2016
20
There is a 6N136 optocoupler in the pwm circuit. In between there are many small surface mount resistors an such. I get a 2.12kohm reading between the pwm pin and the third pin of the optocoupler.
 
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