# Treadmill Blows PCB Fuse on startup... Why?



## CamaLamaDD (Oct 6, 2012)

Hi everyone,

I recently purchased a second hand treadmill from a local. I've ran into problems with the drive motor blowing the 15A fuse on the PCB when it starts up.

If I disconnect the motor leads from the board, the unit will be OK. I can start the treadmill, display screen works fine, the elevation motor runs smooth, no problems.

Once I connect those motor leads to the board, the fuse cooks.

I have re-soldered the positive blade connection to the board because it was quite loose, but that has not made a difference.

I turned the treadmill on with the motor leads disconnected and put a volt meter on the positive terminal... I get 190 volts to ground and around 350 volts from + to - on the board connections. The treadmill motor is rated at 90 volts and 15 amps.

I'm trying to ascertain my problem... bad motor or bad PCB? How can I diagnose exactly the cause of this fuse cooking?

Thanks!


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## ChuckF. (Aug 25, 2013)

-Check literature or search for literature and confirm amps of fuse and whether it is slow-blow or not. Might also be printed on circuit board.
-Look for leaky or swollen capacitors on circuit board.
-Provide closeup picture of circuit board.


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## Protocol. (May 31, 2012)

You can test the motor pretty quickly by taking the belt off the motor and hooking the motor up to a 12v car battery. It should spin, but slowly. Like walking speed. The motor should also spin freely by hand. 

If it does work with a battery, I'd say the board is suspect. 

It's impossible to say if the 300v reading is good or not with no load applied.

At the end of the day, the controller or motor are probably going to be worth more then you're going to want to throw at it.


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## CamaLamaDD (Oct 6, 2012)

ChuckF. said:


> -Check literature or search for literature and confirm amps of fuse and whether it is slow-blow or not. Might also be printed on circuit board.
> -Look for leaky or swollen capacitors on circuit board.
> -Provide closeup picture of circuit board.





Protocol. said:


> You can test the motor pretty quickly by taking the belt off the motor and hooking the motor up to a 12v car battery. It should spin, but slowly. Like walking speed. The motor should also spin freely by hand.
> 
> If it does work with a battery, I'd say the board is suspect.
> 
> ...


Hi folks,

Thanks so much for the info!

The 12V test makes sense, I`ll try it tonight or tomorrow and get back to you.

I do have access to inexpensive replacement parts, so I am interested in seeing what I can do with this. It`s also a learning experience for me, I only have a basic understanding of electronics and circuits.


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## CamaLamaDD (Oct 6, 2012)

Hi again,

The motor ran fine in both directions on an automotive battery. Phooey.

Next suggestion?


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## jmon (Nov 5, 2012)

Reread post 3 by protocol, the board may be suspect.


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## Seattle2k (Mar 26, 2012)

I suspect the power supply board, as well. Here are a couple resources, to help you understand what's going on, in typical AC power supplies:

https://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=psrepair.txt
http://mysite.du.edu/~etuttle/electron/elect9.htm


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## Protocol. (May 31, 2012)

What's the make/model of the treadmill? It's been about 4 years since I've even touched a treadmill so I'll try and remember what I can.

There are a couple other things you should look at as well before you sink a bunch of time into it. Namely the condition of the rollers,belt, and deck. If the decks aren't lubticated, especially on older units. The deck will wear fast, dirt will buildup. And it won't be worth it regardless.

At this point I usually go with a motor controller though. You've conformed that it blows a fuse almost immediately and that the motor itself runs and is OK. Without an actual make/model that's really all I can suggest.


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