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mrf477 final in a galaxy

Discussion in 'CB Radio Modifications' started by freakshow, Jun 18, 2017.

  1. freakshow

    freakshow
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    I purchased a galaxy dx77v for 50 bucks figured it was a good deal it works good and all everyone tells me it doesn't sound as good as my old radio (dx33) but I got curious and opened up the new radio and it looks like it has had a lot of work done to it one thing it has is a mrf477 and here is my question is that a good final for that radio and why would some one go through all that trouble to put it in there


     
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  2. midnight special

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    how old is that radio? wow a mrf477,,, if it is a real 477 i know a few hr 2510 guys who would buy that just for the final,,,,,
     
  3. sonoma

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    if I remember right the 477 does not have the right pin out for a 77 radio. they would have to cross 2 of the legs. Midnight am I thinking of the right part number.
     
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  4. midnight special

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    i think so sonoma,,,there is a final,, i cant remember which one but the legs are crossed for it to fit in the hr 2510,,,,
     
  5. freakshow

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    Yeah they had crossed the legs on the final that's the first thing that got my attention
     
  6. freakshow

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    Probly pretty old the guy I got it from said he bought it for 120 from a pawn shop but couldn't figure it out because it had to many switches but it looks like the real deal with the final it's got the Motorola logo and all on it
     
  7. Low_Boy

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    I recently bought a Galaxy 44 on e Bay and when I opened it up it had a MRF477 with the legs crossed so it could be hooked up. The final was volted and TR32 was cut along with the swing mod on R238. It was doing 50W PEP. The first thing I did was remove the swing Mod and reinstall the limiter. The final MRF477 showed no improvement than a radio with factory 2SC1969. I could not get 100% modulation stock as with most galaxies of that time frame. I clipped R249 and the radio did about 45W It also looks pretty good on the scope. The mod was done back in the 90's by the date written inside the cover. That was a time that the MRF477 was readily available. You are looking at around $50.00 a piece if you can find that final now. I would get rid of all the crap mods so the radio will sound good and leave the 477 in the radio. Chances are if someone tried to use that final in a HR2510 the legs would break off when straightening them.

    HOWDY SONOMA IT HAS BEEN A LONG TIME. HOPE EVERYTHING IS GOING WELL.
     
  8. rabbiporkchop

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    More gain and less heat generated. Whoever did the conversion was a smart man. I suspect that it's been to a couple other butchers after the conversion was done that's why it doesn't sound so good.
     
  9. freakshow

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    It sounds good and clear just not real loud
     
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  10. freakshow

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    If I post a pic of the insides can y'all tell me what's all been done and do you think the radio needs a heatsink since its got that bigger final in it
     
  11. rabbiporkchop

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    When properly functioning, it should sound the same 20 miles down the road as it does in the parking lot you are in. Super loud fades quickly. I suspect the guy that originally did the job limited the amount of gain by changing a resistor value to prevent you from being able to increase mic gain by turning VR14. If it is who I think it is, he did an idiotproof tune, but it sounds like someone else has been inside the radio since then, and they were unable to locate the resistor that was changed. The beauty of the MRF477 conversion is it generates less Heat than the original finals but gives you more gain. You do not need a bigger heat sink for that radio. If it was me, I would use it and see how it performs from a distance perspective and compare it to things that you already own and if it outperforms them I would leave it alone, as increasing the Audio Level will most likely decrease the performance of the radio.
     
    #11 rabbiporkchop, Jun 18, 2017
    Last edited: Jun 18, 2017
  12. sonoma

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    Hey Low Boy, keep in touch. glad to see you have moved on. I have been here for about 10 years now.
     
  13. freakshow

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    Since it sounds clear I think I'm just gunna leave it how it is and get a small amp to give it a little more kick I'm a log truck driver and I just need a little more kick to get through the woods a little further what is a small cheap amp that you guys would suggest that would pair good with this radio and thanks for all the info everyone I'm happy to know that the final in that radio is a good one
     
  14. rabbiporkchop

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    Smallest amp I could think of would require six 2sc2879 transistors.
    It won't be cheap.
     
  15. Low_Boy

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    Yes I would put on a heat sink. The one I have has a heat sink.
     

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