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RM Station 550

Discussion in 'Amplifiers' started by redlght, Dec 17, 2016.

  1. 2RT307

    2RT307 Sr. Member

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    What I remember about this particular amp is the same as all the other RM Italy transistor amps. You have to keep the drive really low. What kind of power are you putting into it?

    73,
    Brett


     
    LeapFrog and 222DBFL like this.

  2. redlght

    redlght Active Member

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    3 watts am 8 sbb adjusting drive level does not help. mine seems top be the same as Bob's board from the other thread.

    I read 36 volts on the collectors of TR 6 & 7 in standby that sound right?
     
    #17 redlght, Dec 18, 2016
    Last edited: Dec 18, 2016
    2RT307 likes this.
  3. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Pins 1 & 2. To me it is oblivious that the bias is not set up properly. How technical can you get with confidence?
     
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  4. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Pins 1 & 2 on the jumper. How technical can you get comfortably? Do you have good voltmeters, oscilloscope?
     
  5. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    According to the manual 1 to 10 watts AM or FM. Read that as dead key power since FM does not change in amplitude with modulation.
    2-20 watts SSB or CW. That's as per the owners manual operating manual.
     
  6. redlght

    redlght Active Member

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    I have most of the test gear needed just not any real voltages to go by and a few differences in the schematic I am going by this one
     

    Attached Files:

  7. redlght

    redlght Active Member

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    Any help would be great
     
  8. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Tomorrow after noon I can set it up and test it. I don't know if it works or not but I'll find quick enough. Certain things like the voltage to the finals should be okay. There are no blown fuses in it.
    But for now I'm dragging my butt to bed.
    I do have ideas of what to check, but that is for tomorrow.
     
  9. redlght

    redlght Active Member

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    thanks and good night
     
  10. 222DBFL

    222DBFL Sr. Member

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    Redlight, Tallman is good people and knows those RM Italy amps pretty well. He will get you an answer. He has worked on a few of those RM Italy amps from what I have heard.:whistle:;)
    Hope you get it working how you want. I do know that all the ones I've heard on air or heard about, don't like a lot of dead key power, and they don't like a lot of PEP power either. Keep the power set low and focus on getting a clean signal out versus how much power you get out of it as long as it appears to be working properly. It might only take .5 watts of dead key or possibly less and about 8-12 watts on SSB and about 8 watts pep on AM to make it work correctly. Like I said, get a clean signal and also a good 1:4 ratio of power. So if it dead keys 40 watts, PEP power should be about 160 watts give or take a few watts. Don't always believe the manufacturers figures for input as you may find it very different from what they are listed as. And that goes for a lot of amps out there, not just yours. JMHO's. And again, hope you get it working the way you would like it to.
    73 and God Bless
    222DBFL
     
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  11. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    I printed out both of the schematics and compared in a couple of places and the reference designators are the same.
    I only took a couple of voltage measurements so far I had to take it all down for Sunday lunch.
    Here is what I read On the collectors of the RF Final transistors 33.8 volts unkeyed. On the Bases of the RF finals .65 Vdc with no signal in put. Manually key the amplifier by taking the collector of TR-3 TO GROUND with a jumper. Don't keep it keyed too long in this condition, just long enough to get your reading. If you have two volt meters monitor the output supply voltage for the radio it should not dip below 12.8 Vdc when keyed.(No radio connected)
    I'm getting ready to scrap this amplifier out and keep just certain parts. If you want it just pay for shipping.
     
    #26 Tallman, Dec 18, 2016
    Last edited: Dec 18, 2016
  12. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Aww shucks, now I'm starting to blush. Thanks 222DBFL.
     
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  13. 222DBFL

    222DBFL Sr. Member

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    I know who knows what! I just tell it like it is!! Hope all is well with you and the lovely Mrs. Its been hot down here. Going to be a beach Christmas LOL!! No cold. But possible sunburn!! Have a great and Blessed Christmas. Soon I'll be catching you on the other bands! February is just around the corner!! Anyways. Have a Merry Christmas and hopefully will talk with you before the New Year.
    73 and God Bless.
    Sean
     
  14. sp5it

    sp5it Master of puppets

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    What is the voltage on emitter of TR9 when amp is on and other switch is on ON position?
    Mike
     
  15. redlght

    redlght Active Member

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    Ill check those voltages today thanks so much for the help and i would pay shipping for the amp message me
     

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