Another treadmill motor board problem

Discussion in 'The Projects Forum' started by dpyle, Sep 2, 2012.

  1. dpyle

    Thread Starter New Member

    Sep 1, 2012
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    Hi, I have an Ironman 220t treadmill with a Keys Health board p/n 08-0158.
    The problem is I can power up the treadmill and everything is fine. But as soon as I start the belt motor F2 blows. I can use my cordless drill battery and run the motor, so it seems good. I don't see any marks or anything on the board. Anyone with any ideas where to start?

    Thanks
     
  2. Rbeckett

    Member

    Sep 3, 2010
    205
    32
    I would start troubleshooting by pulling the plug at te motor. The system will then send all the signals to the motor, but it wont apply that load. If the fuse still pops, look into the board and folllow that circuit till you find the shorted componrnt. If the fuse doesnt pop that confirms that you have a short inside the motor or the wiring leading to the motor. That should at least get you started locating where the issue is. Remember that you are working with mains energy unplug and allow the caps to run down bbefore you put your hands in and get bitten. Avoid contact with the caps still, just in case they contain a residual charge.
    Bob
     
  3. dpyle

    Thread Starter New Member

    Sep 1, 2012
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    OK, the fuse still pops with the motor disconnected. So that means the problem is in the board. My question now is when tracing back I run into rectifiers and capacacitors. Nothing looks burnt. How do I check these?

    Thanks
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    U need to desolder them first
     
  5. dpyle

    Thread Starter New Member

    Sep 1, 2012
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    OK, but how do I check the chips, rectifiers, and caps. I think I remember a plain diode will conduct one direction, but not the other, right? The ones that I'm not sure of though are the rectifier packages, the three legged and four legged variety (I assume they are rectifier packages). :confused:
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,118
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    Others may have different ideas, but I'd be very suspicious of the power transistors that drive the motor. If one of them failed as a short to ground, that would blow fuses.
     
  7. dpyle

    Thread Starter New Member

    Sep 1, 2012
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    Thanks Wayneh, thats bkinda what I was thinking. If you look at the pictures, to my knowledge (which isnt muxh) I see only one transistor. If I unsolder it, how do I test it?
     
  8. gerty

    AAC Fanatic!

    Aug 30, 2007
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    I would also check the bridge rectifier (marked BD1, lower left first picture).
    That too should be removed from board to be checked.
    You would check the bridge by using a meter in the "diode" setting and check across all the pins one pair at a time. An obvious short should give you a
    ".000" reading.

    When removing any components for checking, always make a note of the parts orientation so that you don't put them back in backwards.
     
    Last edited: Sep 6, 2012
  9. wayneh

    Expert

    Sep 9, 2010
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    Trust me, that's sage advice. ;) Been there, failed to do it.

    Those big black, 3-pinned components that stand vertically off the board - those are potentially the power transistors. It looks like one of them is Q11. They can also be tested with your meter's diode tester (after removing them from the board).
     
  10. dpyle

    Thread Starter New Member

    Sep 1, 2012
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    So if I get a .4190 across a couple pins and an open (OL) across others it is good? (using a digital meter with a diode setting).
     
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