Icon MC2100LT-12 Treadmill Controller Not Powering Main Motor

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
I have a Gold's Gym treadmill that everything seems to work on except the main motor.--You can adjust the incline, it takes your heart rate, counts how long the treadmill has been running and calories you've supposedly burned, and you can change the speed setting, but nothing happens with the main motor. The leads that should be powering it just show continuity from one to the other.

The treadmill came with a sheet that lists LED diagnostic codes. The LED on the controller board is not lit at all. Unfortunately, the condition listed for 'LED not lit' is 'no power.' But it does have power. There is AC power going into it (so I know the motor overheat switch is okay), and it's powering the console and incline motor. So the disagnostics aren't especially accurate or helpful. I was hoping someone who's familiar with this (fairly common) controller might be able to shed some light on how to diagnose and repair it. I can get a new one for ~$60, but I wouldn't learn anything by just replacing it. It would be awesome if I could actually ferret out the problem and fix the board that's in it.

Thanks in advance for any insight you might be able to provide.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
Printed on the board, it says:

MC2100LT REV
ICON 2006


And on a sticker on the board, it says:

000 1341 MC2100LT-12 226706A
 

MaxHeadRoom

Joined Jul 18, 2013
19,198
MC2100 board, there were a couple of versions,
Post a pic if possible.
There is a reverse-engineered schematic in the forum here with a search.
Maybe the board has power, but is the 12v present?
Max.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
I'm not great with electronics, trying to learn a little. I've replaced a swollen capacitor here and there and whatnot, but nothing too in-depth. I'll see if I can make sense of the schematic. I have a multimeter ordered so I can do more detailed testing instead of just voltage and resistance. Picture of the board is attached.1573940911137451086347416749350.jpg
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
I do get 13.3VDC between the red and black wire on the 8-wire connector that goes up to the control console. I have a more advanced multimeter now and am figuring out how to test diodes and transistors and whatnot. I thought I'd test a few things and look for anything obviously wrong, but I'm not getting results consistent with what I expect, and I'm wondering if that's due mostly (if not entirely) to the fact that the components are installed in a circuit muddying the waters.

I am getting 1/1 (fwd bias/rev bias) on all diodes except D10 (654/1) and D13 (412/1), other than D6 & D8 which are silkscreened onto the board, but I don't see a corresponding diode. (?) Wasn't sure if that means they're bad, or just due to them being installed in a circuit. I don't know if any of that is helpful. What should I be testing?

You (Max) told someone else "The first thing to suspect is the power devices attached to the aluminum heat sink, test these first." I don't see identifying marks on them, so I'm a little lost at how to test and how to interpret the results. Any insight would be most appreciated.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
Also, I just tested the motor itself with the inverter in an old UPS, and it does work, so this is 100% a controller problem.
 

MaxHeadRoom

Joined Jul 18, 2013
19,198
The Mosfet is a IRFP250 next to it is a rectifier DSE130-06A, the main power rectifier on the end of the H.S. is a GBJ25G bridge.
That is the MC2100 LT version, not sure what the LT stands for as the power devices appear to be the same as the non LT version.
Max.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
On the bridge rectifier, I get 84 across the 2 center leads in either direction with my meter on diode test mode, which I believe means that guy is bad. If so, could that be the cause of all of the symptoms I'm seeing?--Everything acting normally except status LED not lighting at all, and no voltage being sent to the motor? If so, does it make sense to do a direct replacement? Or should it be upgraded? Is there likely something else wrong that caused it to fail? If so, what are the likely causes?
 

MaxHeadRoom

Joined Jul 18, 2013
19,198
On the bridge rectifier, carefully measure the DC voltage on the two outer leads, the two inner ones are the AC supply. You should see >140vdc
Max.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
Okay, sounds like it's good then. That's one potential culprit I can check off the list. Cool. Thank you.

What kind of readings should I look for from the MOSFET?
 

MaxHeadRoom

Joined Jul 18, 2013
19,198
The fact that the LED does not light could mean a problem elsewhere, the PicMicro itself?
I can take some more reading of the drive operating, it will be useful for future anyway.
May be today or tomorrow.
Max.
 

Thread Starter

Dapostrophus

Joined Nov 15, 2019
17
Also, even with a magnifying glass, the lettering on the PicMicro is unreadable. I can't find it listed anywhere what model it is. Do you have that information? Just wanted to look up that chip in case I need to replace it. If I do, it will not be pretty, but I have a plan.
 
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