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Looking inside FZR 250 Cdi unit

Discussion in 'Yamaha 250cc In-Line 4's' started by Grasshopper, Feb 20, 2014.

  1. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    image.jpg Hi, when we got the bike, the owner had the old faulty unit, so I opened it up to have a look inside. I understand that not only is it a Cdi unit, but also controls the exup and other ignition type functions?

    I did not have a small hobby saw, so I used a heat gun (read soldering iron.... Oops!) to cut the plastic case, as you can't pull the pcb out as it is glued in with contact type glue. Photos follow:

    image.jpg

    Now opening her up.....

    image.jpg

    image.jpg

    image.jpg

    And here's the other side of the pcb........

    image.jpg


    Ther's a lot more to it than I thought there would be..... ( Eg. the large IC etc) Any comments?
     
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  2. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Got me stuffed. Where do the points and condenser go?
     
  3. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I know this thread is a couple of year's old, but by any chance do you still have this TCI ?
     
  4. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    they're not that complicated - basically the larger transistors will often crack if they fail, the only components which wear out in those units are the electrolytic capacitors because the electrolyte in them slowly escapes due to normal usage.

    the large IC is just a processor with an EEPROM but PDF's for the specs are almost impossible to obtain

    When I had mine apart and replaced all of the caps I noticed there wasn't a lot else to go wrong and most potential failure parts are obtainable
     
  5. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah, i do a lot of electronic repair's myself too, tv's, radio's and everything in between
    I just want another one to compare the reading's with mine
    I reckon the transistor's might be on their way out, they can fail without any sign's too same with the resistor's, capacitor's and diode's.
     
  6. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    for what it's worth it's simple enough to replace most of the potential culprits in one hit - it's a really bad diagnosis strategy, but transistors, resistors and diodes are simple enough to test, or just replace them.

    When I searched years ago for the main IC datasheet I was hoping to potentially suck the EEPROM data off and decode to potentially change it and reflash - AAH pipe dreams
     
  7. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    I still have it somewhere I think.... I've seen replacement ones somewhere (non-Yamaha....).... I have done Eprom programming in the past... (a long time ago)...
     
  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yeah it would have been great to be able to reprogam them or at least extract the ignition parameters to potentially repair them in the case of failure
     
  9. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Aliexpress sell them for around $80 and up but they're all for 2KR's
    I have a non exup 2KR TCI here that i've pulled apart but they are very basic compared to the 3LN3 TCI
     

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