need help with an ignition on a golf cart

Discussion in 'The Projects Forum' started by bigbri, Aug 2, 2011.

  1. bigbri

    Thread Starter New Member

    Aug 2, 2011
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    Hi new to the forum. I have a 1988 2 stroke columbia golf cart and my ignition shot craps. It has an electronic ignition. The cart is old so parts are expensive. 200.00 for the ignition. It uses a magnet on the crank shaft and I believe a hall effect sensor. The sensor is covered in a hard paste. Anyone have a curcuit i could use to replace it?
     
  2. debe

    Well-Known Member

    Sep 21, 2010
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    For help here it a good idea to post a few good pictures of the parts & where they are fitted to the machine.
     
  3. bigbri

    Thread Starter New Member

    Aug 2, 2011
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    The solid state ignition is mounted on a metal plate that is attached to the cover of the crank shaft. It has a plastic ring that has 2 magnets that spins on the crank shaft. The ignition has 2 wires a blue one that goes to the + side of the coil. The black one goes to the - side of the coil. The coil has 12v on the + side that comes from the gas petal. The wire on the - side supplies a grnd to the - side. Just like a points system. Actually I was told that some people get parts from older golf carts and replace the ignition with points and condensor because of the price .
     
  4. bigbri

    Thread Starter New Member

    Aug 2, 2011
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    Here is a diagram of the front of the engine. part is #22 ignition module and #21 rotor with magets. The magnets are one south and one north. I hope that helps.
     
  5. debe

    Well-Known Member

    Sep 21, 2010
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    Hi Bri, Now were of to a good start the RCA9202 is a NPN darlington power transistor Vebo 400v @ Ic 4amp. This will be the switching transistor for the coil & most probably what has failed. This would be the first thing i would replace if you can get one, or if some one can sugest an equivelent to replace it. If that doesnt work the other part TL170C is a Magnetic field sensing Hall efect switch, this is what trigers the transistor, unlikely but may be faulty. Very interesting & simple circuit. Can you post a better (clearer) picture of the component side of the circuit board very out of focus. This should be repairable if components can be sourced.
     
  6. debe

    Well-Known Member

    Sep 21, 2010
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    This is as close as i can get to a circuit, 2 un known parts 1N33A some sort of protection diode? 2504Zenamic another unidentified protection? any other sugestions? Also if the RCA transistor is unavalable does any one know what suitable darlington transistor is avalable as a replacement?
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Here's an upgrade for the RCA9202; the OnSemi MJE5742
    http://www.onsemi.com/pub_link/Collateral/MJE5740-D.PDF
    Same pinout, rated for 8A vs 4A, 80W vs 65W, 400v (both); about the only thing different is the gain is a bit less @ 25°F (500 vs 750), but once it gets warmed up it has more gain than the original. I don't think the gain will be an issue.

    Digikey stocks them for $1.95/ea when you're buying 1.
    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MJE5742GOS-ND
    Mouser stocks them for $1.76 @ 1/ea
    http://www.mouser.com/ProductDetail...=sGAEpiMZZMupZfs/wBb3DIV36EBDkL3Ol8luVVsxz1o=
     
    debe likes this.
  8. SgtWookie

    Expert

    Jul 17, 2007
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    The Zenamic I think is a MOV.
    The 1N33A should be some kind of point-contact germanium diode; can't seem to find them. You could probably replace it with a 1N5819 or other Schottky diode rated for >=40v, 1A. The germanium diodes had a low forward voltage, but after Schottky diodes came out you hardly ever see germaniums anymore; the Schottky diodes also have a low Vf, but are much more rugged.
    [eta]
    I take it back, the 1N34 was the first germainium diode - so I guess the 1N33 was a silicon diode. I suppose almost any modern silicon diode would be an improvement.
     
    Last edited: Aug 4, 2011
    debe likes this.
  9. bigbri

    Thread Starter New Member

    Aug 2, 2011
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    sorry that is not my picture. I got that from some else that has the same problem. My iginition module has a white paste on it to protect it from grease, oil and water. I am stilltrying to remove most of the paste.

    Thanks

    Brian
     
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