1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

New Uniden pro520xl dead key adjusting

Discussion in 'Amateur Radio Modifications' started by Roadhog, May 17, 2018.

  1. Roadhog

    Roadhog Member

    Joined:
    Apr 25, 2018
    Messages:
    3
    Likes Received:
    0
    How do you adjust the dead key on a new pro 520xl? I would like to run a small amp with it. Any suggestions? Info?


     

  2. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

    Joined:
    Oct 23, 2017
    Messages:
    1,706
    Likes Received:
    1,545
    Welcome to WWDX! I just checked CBtricks website and they don't seem to have any information on this radio. Maybe someone here can point you in the right direction.
    Chris
     
    Roadhog likes this.
  3. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    2,802
    Likes Received:
    2,596
    That radio does not contain an adjustment for this.

    You will find that most SSB CB radios made since 1980 or so will have an adjustment for AM carrier power.

    Your radio is built for AM only. Nearly every CB of this type requires parts to be added if you wish to reduce the carrier power without also reducing the modulated "swing" power of the radio at the same time.

    I have none of the technical info on hand that's needed to to be specific about how to do it on this model.

    Short version, it has to be modified to reduce the carrier power, far as I know.

    73
     
  4. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

    Joined:
    Apr 23, 2018
    Messages:
    2,068
    Likes Received:
    1,870
    Ok, gotta' ask...

    You are aware that this may not be the proper location in the forum for this thread, you may want to Segway over to another board - IN This Forum - so we don't bother those that may take offense to this procedure...

    Open that baby up and tell us what you see...

    What you tell us, can help us, tell you from us, what can be done...

    There are at least 3 types of Pro-520's out there...

    AXL - kit with an antenna
    XL - basic Radio

    XL model though - came in several "flavors".

    One was Discrete - I can help you with that -anyone can - for they can be "jumped" with an RC mod for swing and power adjustments for matching to a Leen-yar..."

    Another was more compact and used a lot of surface mounts - but you still had some breathing room to remove a coil that went to the Driver so you can still install an RC mod like above.

    The ones I'm seeing lately are SMD (Surface Mount Disasters) meaning they have all the small parts and coils fixed onto a single board and no way to modify it easily using everyday household tools, cleaners and small power tools...

    So, do like they do at those car dealerships - open the hood, snap a photo or two - and let us know what you find...

    :+> Andy <+:
     
    #4 Handy Andy, May 22, 2018
    Last edited: May 22, 2018
    CB590 and Shadetree Mechanic like this.
  5. Kf8tc

    Kf8tc New Member

    Joined:
    Mar 4, 2019
    Messages:
    1
    Likes Received:
    1
    I have the same radio, it uses the surface mounting technology. It is just out of the box. I want to adjust it for almost maximum average power out. I seen where this radio can squeeze out 28w. But the guy wouldn't tell what he did for that performance. I used to be a radio tech many moons ago. I don't just start turning things to see what happens.
    I have not been able to find a schematic to this newer board anywhere. I do have a scope and watt meters and swr meters. I don't want to make a splatter box, so probably not cutting or taking out anything. Probably just some proper peaking. I will hook it up next week on the bench to see what I can do with it. I will post a photo of the board if it will let me. I am going to install it in my motorcycle. I will post my findings if anyone is interested.
     

    Attached Files:

    Shadetree Mechanic likes this.
  6. Dmans

    Dmans Well-Known Member

    Joined:
    Jan 22, 2017
    Messages:
    550
    Likes Received:
    446
    RT201 for TX Power adjustment. It's marked right on the board.

    73's
    David
     
    Shadetree Mechanic likes this.
  7. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

    Joined:
    Oct 23, 2017
    Messages:
    1,706
    Likes Received:
    1,545
    Welcome!
     
  8. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

    Joined:
    Apr 23, 2018
    Messages:
    2,068
    Likes Received:
    1,870
    The SMD technology in it, means it is pretty much "trimmed up" for simple basic performance.

    If you look carefully, we cannot help you for the shield is covering the very area that you asked for help on.

    So as I can reach over and get a SIMILARLY designed SMD Pro510/520 but again that would not help you for your current model used encoder and uP technology, not PLL like a standard IC and VCO circuit. That's the shield plate on the top of the phenolic side of the board.

    So until you remove that plate, I can't even guess as to where to start.

    But I can show you this...this is a snippet of the Final Circuit and it's Tank coupling coil...you can try and extrapolate from that. I see you're licensed so that helps provide you with a "key" to obtain more resources to help you learn from this.
    Pro510Translate.jpg
    Follow the color coding for easier translation. But due to the SMD and that plate, I cannot help you to even know what they biased the replacement of the 2166 from the older days - for even my version of SMD still uses the 2078 - but you may have (due to the shield plate alone) a MOSFET final design that adds complexity to your challenges.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!