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Galaxy schematic-959 duel final

Discussion in 'CB Radio Modifications' started by Larry A McClanahan, Jun 26, 2018.

  1. Larry A McClanahan

    Larry A McClanahan New Member

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    Does anyone have the mod to convert a Galaxy single FET to a dual final mosfet?


     

  2. sonoma

    sonoma Sr. Member

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  3. rabbiporkchop

    rabbiporkchop Well-Known Member

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    The Motorola mrf477 is a more efficient mod and produces less heat, assuming it was originally a bipolar transistor.
     
  4. Larry A McClanahan

    Larry A McClanahan New Member

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    I,m looking to ADD 1 irf520 FET. I was hoping maybe someone had already done it. Or at least did it to a similar chassis.
     
  5. loosecannon

    loosecannon Sr. Member

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    many have done it, and i have a "tutorial" of sorts posted somewhere here on the forum, but it's not a simple plug-and-play type of mod.

    It takes some work and tuning to get it to work right since all radios are a bit different.

    so, you may install it and it works like a charm, or you might install it and find that it acts like the second final isn't even there.


    If you don't have the skills to know what to do if/when this happens then i would not recommend trying this mod.
    LC
     
    rabbiporkchop likes this.
  6. sonoma

    sonoma Sr. Member

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    the links I left you are the mod you are asking about. did you even look at them?
     
  7. Larry A McClanahan

    Larry A McClanahan New Member

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    I am looking at them right now Sonoma. You are top-notch. I love the way you help people out on here. I don't think there's anybody much better my friend. Thank you so much.
     
  8. loosecannon

    loosecannon Sr. Member

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    sonoma, i think the links you provided are for radios that start with bipolars in place.

    I believe Larry is looking for a mod sheet that lays out how to turn a single MOSFET final radio into a dual MOSFET final radio.
    LC
     
  9. Larry A McClanahan

    Larry A McClanahan New Member

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    Yep,
    Add a second IRF520
     
  10. Larry A McClanahan

    Larry A McClanahan New Member

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    Got it covered. I have been troubleshooting and repairing radios since the early eighties.



     
  11. loosecannon

    loosecannon Sr. Member

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    cool.
    all you have to do is compare the schematics of the mosfet version of the DX959 to the schematic for the mosfet version of the DX2517 and add the missing parts.
    (found here: http://www.cbtricks.com/radios/galaxy/index.htm )

    other than that, there is a jumper to add which should be pretty obvious from comparing the PC board layouts, and you have to convert L35 from a 7 turn coil to a 4 turn coil.
    LC
     
  12. Larry A McClanahan

    Larry A McClanahan New Member

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    Thank you. That is the solution I have been looking for. I was not aware that they were the same board. Fantastic. After I do one I might make up a kit for sale on eBay.



     
  13. loosecannon

    loosecannon Sr. Member

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    Larry, all i can say is more power to ya with regards to a kit that yields consistent results.

    This was popular and sought after about 10-12 years ago, and there were a few who had kits on ebay for this.

    the problem is that each radio is different and each radio has to be made to work with this mod in some way.
    some radios may wake right up with just the requisite components added, but some will just ignore the second final as if it's not even there.

    these radios need to be worked on by someone who understands the concepts behind the mod, and basically, anyone with the knowledge to make it work consistently won't need to buy the mod because they will know how to figure it out for themselves.

    If you do decide to put together a kit, be sure to try your method in a BUNCH of different DX959's so you will know it will work.

    please post back with your results!
    LC
     
  14. sonoma

    sonoma Sr. Member

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    this is a lay out for the dual mosfet final setup. yes I know what he is wanting to do but this will help him see just what he needs to do to convert the radio to dual finals..
    I have used this layout 3 times now and only 1 time I had a problem getting the out put past 20 watts. Rick from euro radios helped me to get the radio to put out more.
    this layout drawing will help you to see just what is needed to fill in all the empty spots.

    http://www.cbtricks.com/miscellaneous/fet_papers/mosfet_conv/graphics/6900xxx_ssb_mosfet.pdf
     
  15. loosecannon

    loosecannon Sr. Member

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    you're right Sonoma, that is a good layout to have around when experimenting with this mod.

    I think i actually used it when i developed my personal version of it way back when.
    LC
     

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