MC-60 Motor Control board problems

Discussion in 'The Projects Forum' started by Bobkat, Dec 19, 2012.

  1. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    I have an mc-60 control board that does not start the motor or run the motor on my old treadmill.
    Choke is closed so I eliminated that, console pot works. Breaker is good. I have a spare motor and that will not work with the board either. I tested both motors and they will spin when I hook them to my 12v PS.

    spd ctrl led will light when the console pot is on. 12v led is always lit when ac is applied. I get 54vdc out of the motor spades on the board( a+ a-) if the wires are disconnected but no voltage reading if the motor is connected.

    What is a good plan of attack? I don't have an oscillator that I can use but I do have a good fluke meter to test with.I have been toying with electronics since the age of 14 and can solder pretty good, but unless it's an obvious thing I am lost.

    A new board is something like 83 bucks so I'm hoping I don't have to spring for that. Treadmill is 18 years old but the belt is good and I am hoping to keep it going.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    You need a circuit diagram or another pcb to compare..
     
  3. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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  4. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    Here is a pic of the board
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  6. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    Thank you Dodgydave

    Label on it is looks like TLP3021 but I assume it's a MOC3021
    Is there a way to test out the optocoupler?
    Does anyone know if there are other components that commonly fail on these controller boards or that should be replaced while I am at it?
    I did see a couple separated resistors that I soldered back together. On further reading I find the factory cuts certain resistors depending on application. there is one called 6-8 mph that was in bad shape ( r37) I am not sure if that should be left disconnected.


    Edit: I jumped out the SCR LED and the motor works normally. I did find an optocoupler at a local store for 3.99 so I'll go get that. hopefully they'll have an LED also. I think it's .64 at digikey but the shipping charges make it more expensive.
     
    Last edited: Dec 20, 2012
  7. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Did you look at the datasheet of the TLP3021 and the MOC321?
     
    Last edited: Dec 20, 2012
  8. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    I got a NTE3048 which cross referenced to the TLP3021. I guess they are different from the moc3021. MOC3021 crosses to a different optoisolator .. now to figure out which is pin 1 on the nte as there is no dot there? The data sheet on the nte web site for that optoisolator shows a dot on it to locate the pin 1. Maybe I have to call them tomorrow to find out. Or would it be on the side with the stepped area?

    The old one on the right in the picture has a nice indentation marking pin 1

    DATA sheet on the new component:
    http://www.nteinc.com/specs/3000to3099/pdf/nte3048.pdf
     
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    Last edited: Dec 20, 2012
  9. tubeguy

    Well-Known Member

    Nov 3, 2012
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    I looked at the photo before reading and thought as you did.. the stepped side.
    Why not checK for the LED as you would a diode if you have a meter handy?
     
  10. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    Beveled edge is the indicator for this component for the side with #1 pin
     
  11. Bobkat

    Thread Starter New Member

    Dec 17, 2012
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    Got it going, first time didn't go but I found I messed up the trace from pin 6 to D6. Made a wire out of the extra they gave with the led and jumped them below the board with that.
    Works normally now :) ty all for the help
     
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