NordicTrack ZS Treadmill MCB problem.

Thread Starter

fredz0003

Joined Mar 22, 2012
9
Hi everyone, I have some background in electrical and mechanical systems, but when it comes to this kinda stuff and without a schematic, I'm a little lost. I know this MCB Motor Controller Board is bad because I swap it with a good one from another treadmill, so my manager is going to order a new MCB. But I would like to fix this one and hopefully learn more about electronics, I do have some background but never really used it at all. So to explain about the problem, when I turn on the treadmill, the display comes on and off, and the speakers sound like a heartbeat, I knew there was a problem with the voltage, so I put me analog meter on the display connector attached to the MCB and I can see the voltage fluctuate from 8 to 10dc in rhytm with the heart beat. I couldn't find any schematics to help me with this adventure I just don't want to throw out a possible good board if I just have to replace some components, I do know how to solder and everything. Another thing is that here in houston we have lots of lighting and loss of power, this particular machine didn't have surge protection, so I don't know if this could have been the problem to begin with. I do have more pictures, I will upload when I get home.

Thanks for you help.
 

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R!f@@

Joined Apr 2, 2009
9,918
Try removing the large two transistor type packages mounted on the sink and test for voltage fluctuation. Do not connect motor during this test.
 

#12

Joined Nov 30, 2010
18,224
When it comes to this kind of stuff, without a schematic, everybody is a little lost, (unless thay work at the Nordic Track factory) and photos will not fix that.

Anybody here work at Nordic Track?

If nobody responds, try to post a schematic.
 

Thread Starter

fredz0003

Joined Mar 22, 2012
9
When it comes to this kind of stuff, without a schematic, everybody is a little lost, (unless thay work at the Nordic Track factory) and photos will not fix that.

Anybody here work at Nordic Track?

If nobody responds, try to post a schematic.
I will try to draw schematic, this is not a needs to be done now project, just for DIY learning kinda thing trying to learn electronics, I will draw schematic and post as soon as I can, just for FYI, where it was fluctuating it was the lower, left corner on that pin connector next to those black caps, it looks like from the switching transformer, it get 67AC V, then it spits out 12VDC, goes to the transistor, those caps, and a couple of resistors. Thats where the display connects, and it comes on and off.
 

#12

Joined Nov 30, 2010
18,224
Without a schematic, it could be anything from a faulty regulator to a "self protection" method that the board is using to avoid smoke escaping.

ps, it looks like a high speed switching supply. They can get upset by capacitors that are getting old and feeble, but I'm only guessing at what I'd examine next.
 
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