MC-60 Motor Controller won't turn on. I need help

Thread Starter

ElectricSuperSaiyan

Joined Sep 26, 2020
5
Hello, I received a treadmill that would not start. Treadmill powers on the console, there's lights on what seems to be the power supply board, but no lights come on the mc-60 board. I saw a video on YouTube about how to use the mc-60 controller board to force the motor to turn on as many people have used this board to make drills and sanders etc. I followed the instructions exactly and when I plugged it in (bypassing the treadmills power supply and controlling it with my own potentiometer) the treadmill motor immediately started at full speed and smoke was coming from the mc-60 board. I know there is much discussion about this board and I have read a couple of threads, but I need help narrowing down to what the issue could be. I am thinking that the SCR S4020L thyristors are burned. When I put my multimeter and tested in diode mode, I am only getting 0.023 V from the very left edge lead to the right edge lead. I read that by shorting the anode with the gate while keeping negative lead of multimeter to the cathode, I should be getting 0.5-0.7 V reading or so. But when I short, its the same reading 0.023 V.

I apologize , I am a beginner in electronics but I am going through the textbook here in this awesome site that I wish I knew about before. I know there is a schematic here about this board but when I see it, it makes no sense to me. Plain English answers would greatly be appreciated. Thank you in advance for any assistance given.
 

Thread Starter

ElectricSuperSaiyan

Joined Sep 26, 2020
5
Okay I unplugged control pot and motor does not run. There are no lights coming on mc-60. I have everything connected normally to the treadmill except red white and black cable. Attached a photo.
 

Thread Starter

ElectricSuperSaiyan

Joined Sep 26, 2020
5
First just power up the board with no control pot attached, and ensure the motor does not run.
Check for D7 lit.
Max.

Okay I unplugged control pot and motor does not run. There are no lights coming on mc-60. I have everything connected normally to the treadmill except red white and black cable. Attached a photo.
 

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MaxHeadRoom

Joined Jul 18, 2013
22,823
Where did the smoke emanate from?
I would trouble shoot the board in a stand-alone condition, i.e. power it directly to the AC in from a switched AC source/socket.
First try with a incandescent lamp with the pot connected and see if it ramps up and if any LED lights.
Max.
.
 

Thread Starter

ElectricSuperSaiyan

Joined Sep 26, 2020
5
Where did the smoke emanate from?
I would trouble shoot the board in a stand-alone condition, i.e. power it directly to the AC in from a switched AC source/socket.
First try with a incandescent lamp with the pot connected and see if it ramps up and if any LED lights.
Max.
.
Where do I connect the incandescent lamp to? The motor leads on the board?
 

MaxHeadRoom

Joined Jul 18, 2013
22,823
Yes, the motor leads, no motor connected.
The ind LED should turn on with a command.
The power LED should light if there is the 12v source present.
Max..
 
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