Troubleshooting an ICON U-MC2100E treadmill motor controller

Thread Starter

dipak.jha

Joined Jun 5, 2018
3
Guys,

I am trying to repair a 6 year old Weslo Cadence 21 treadmill.

The problem began with this treadmill having difficulty starting up. But for a few days, I could get it running my applying an initial manual push with my legs. Once started, it would keep working unless I left it alone and switched off for a few hours.

However, finally, it has stopped completely. The main DC traction motor refuses to start, whatever I do.

I took the cover off to discover that it has a U-MC2100E motor controller board. Using a multimeter, I can see the AC input to the board is fine. However, the DC voltage to the motor is always zero. The single LED on the board is lit up when power is supplied and stays a solid red without blinking. No signs of damage or leak on the main 400v / 560uf capacitor. Other components also look ok, visually and the console beeps happily when power is switched on.

Incline actuator works fine along with its cooling fan.

Pictures of the controller are attached

Could you please give me any indication on how I could go about troubleshooting the board and which specific electronic component(s) I should try replacing? Also, can the controller board be repaired at all or am I better off buying a new board? It is priced at £125 which makes me thing buying a new treadmill altogether may not be a bad idea

Any pointers would be most appreciated
 

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Thread Starter

dipak.jha

Joined Jun 5, 2018
3
Have you done a search here yet using MC2100?
There have been several posts on this model of T.M. controller.
Max.
Hi,

Thanks for your response. Yes I have but couldn't find a close answer to my questions. I know troubleshooting such a circuit should really be a scientific, data-driven approach but I was wondering if the knowledge-base of this forum can be tapped into to arrive at the "best guess" about the faulty component BASED ON my described behaviour of the treadmill just before it died. My experience suggests it could be that big 400v/560uf capacitor but I could well be off the mark.

Regards,

Dipak Jha
 

Thread Starter

dipak.jha

Joined Jun 5, 2018
3
The first thing to suspect is the power devices attached to the aluminum heat sink, test these first.
Max.
I've replaced all (four) power devices attached to the heat sink. The main capacitor has also been replaced. But the problem persists.
I am not sure what to look at next. Please help

Regards,

Dipak Jha
 

Mckeopj1

Joined Jul 28, 2018
2
Hi ,
Having the same issue .
The led stays contantly on . From google I assumed it was the PWM but it wasn’t .

Any thoughts or drawings . I hoped to only use the power supply from this but A+ and A- is confusing . They both seem to have a 125v potential to earth .
 

Mckeopj1

Joined Jul 28, 2018
2
Thanks for all the info. This board might get be above me as it is not as simple as I hoped . (Unlike me)
I checked the pwm operation all be it with a multimeter and it did change with a change in speed on the controller display . Sorry I didn’t have a scope to check the correctness of the pwm.
The LED is on constant regardless .

I hooked up a external pwm with a batttery to the motor and it controlled just fine . So I hopefully can rule out the motor now.

So I still have some issue on the board . I thought it might be opto isolators but the two of them respond when and input is applied .

So now I’m thinking that I have power on the board and the possibility to use the external pwm to drive the motor . I’m limited to 80v on the pwm . So I’m looking at taking power somewhere after the bridge rectifier but it is 125v potential and I’ve learned also it’s isolated from earth .
 

MaxHeadRoom

Joined Jul 18, 2013
20,925
So I’m looking at taking power somewhere after the bridge rectifier but it is 125v potential and I’ve learned also it’s isolated from earth .
With this controller the motor power is referenced to earth ground as there is no galvanic isolation from the AC input, via the grounded neutral.
A resistance test would not be conclusive.
You would need to do a AC conductivity test.
Max.
 

F8FFV

Joined Mar 28, 2020
1
Guys,

I am trying to repair a 6 year old Weslo Cadence 21 treadmill.

The problem began with this treadmill having difficulty starting up. But for a few days, I could get it running my applying an initial manual push with my legs. Once started, it would keep working unless I left it alone and switched off for a few hours.

However, finally, it has stopped completely. The main DC traction motor refuses to start, whatever I do.

I took the cover off to discover that it has a U-MC2100E motor controller board. Using a multimeter, I can see the AC input to the board is fine. However, the DC voltage to the motor is always zero. The single LED on the board is lit up when power is supplied and stays a solid red without blinking. No signs of damage or leak on the main 400v / 560uf capacitor. Other components also look ok, visually and the console beeps happily when power is switched on.

Incline actuator works fine along with its cooling fan.

Pictures of the controller are attached

Could you please give me any indication on how I could go about troubleshooting the board and which specific electronic component(s) I should try replacing? Also, can the controller board be repaired at all or am I better off buying a new board? It is priced at £125 which makes me thing buying a new treadmill altogether may not be a bad idea

Any pointers would be most appreciated

Hello Dipak, do you have the final conclusion. I am confronted with same issue, so your final findings would help. Thanks a lot
F8FFV
 

MaxHeadRoom

Joined Jul 18, 2013
20,925
If the LED stays solid as per the OP's, then it usually indicates a loss of signal onto pin 4 of the HD2 socket, you could meter it with reference to pin 1 (GND).
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
20,925
That is a Mosfet driver, the versions I have, the U4 is a triac opto MOC3052.
The motor Mosfet gate is fed from a MIC4427, Mosfet driver for the IRFP250.
Max..
 
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