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

8 volt source? Uniden Pro520xl

Discussion in 'CB Radio Modifications' started by Cutlass327, Sep 18, 2018.

  1. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    Trying a new echo board, a Ranger EB-2015. It has "DC input 8v" for the power connection that you usually put to the radio on/off switch.

    Is there an 8V source, or is this just put to the power switch like normal?

    If there is, I need an 8v source on the 520xl and a Cobra 25 NWSTWX if at all possible?


     
    Shadetree Mechanic likes this.

  2. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    1,946
    Likes Received:
    1,377
    Don't worry about finding a source of + 8 Volts DC.

    That board has a voltage-regulator chip on it. Should tolerate running from the radio's main 13.8-Volt power just fine.

    73
     
    Shadetree Mechanic likes this.
  3. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    Awesome, thanks!

    This is one of those new models, very spacious for its size...

    Also looks like the tuning for the old ones won't work. There are 3 pots right in the middle, one labeled TX power, one RX, and one Squelch... Odd they made them so easy to find.
     
  4. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    1,946
    Likes Received:
    1,377
    What makes it look spacious on the component side of the circuit board is that the parts are all (nearly) on the solder side.

    The Tx power trimpot is for the meter, not the actual transmit power.

    73
     
  5. psycho

    psycho Running a special on our rooms!

    Joined:
    Aug 25, 2006
    Messages:
    3,390
    Likes Received:
    1,161
    Coibra 25 soundtracker and a 520XL????? At least you won't be ruining good radios.
     
    9C1Driver and Shadetree Mechanic like this.
  6. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    Start simple, right?

    Don't want to ruin my Galaxies while refreshing my brain on this stuff.
     
    Shadetree Mechanic likes this.
  7. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

    Joined:
    Oct 23, 2017
    Messages:
    969
    Likes Received:
    698
    I run a 510 in my stake body truck. It has never failed me. Modifying the radios is what hooked me on the hobby. More power to you.
    Chris
     
  8. psycho

    psycho Running a special on our rooms!

    Joined:
    Aug 25, 2006
    Messages:
    3,390
    Likes Received:
    1,161

    I don't know where you can put an echo in a 520, you might need to sticky tape it to the top of the case. LOL
     
  9. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    This one is small. I dont think it is even 2" square. There is also a little bracket on it and a screw to bolt it to the side of the chassis. The hardest part is to figure out where to put the controls!

    The radio itself is a lot of empty space inside, all surface-mounted components.
     

    Attached Files:

  10. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    Well, I got it in there. The eBay seller "s9cb_radios" who I bought it from helped me out a lot! There is a voltage regulator on the side of the chassis under a metal cover that has the line in volts, ground, and 8V output. Hooked it to that, it worked. Had to turn the output on the echo board to max, but wasn't happy with what I heard over my base radio - wasn't clear and loud. Same board in the 25 sounded perfect, and didn't have to turn it up. Dunno if it has to do with the "high impedance microphone" part of the 520. I took it out. And for what it is worth, a 68 Ohm across PA and Ext speaker worked perfect for talkback, even though I had found somewhere on here someone said it didn't work.

    I'm putting that board into a 2nd 25 I have, maybe I can fit it into my Focus where I squeezed the 520...
     
  11. Handy Andy

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

    Joined:
    Apr 23, 2018
    Messages:
    1,546
    Likes Received:
    1,251
    The 520 uses a Electret Mic - supplied power by the Mic wire to the Element and audio - got both power and audio thru the mic cord as you use it.

    So perhaps your issue was with the Electrets' Power interface - that can screw up the Echo real fast.

    You have the SMD (Surface Mount Device) board in there. This makes it tougher to choose where to inject as well as sample the audio. All the traces and parts are on the bottom - or top - depending on how you mount the radio and use it.

    Now had you used the Echo boards own Mic Amp, it's strong enough to drive the Audio amp directly - you can remove a couple of mainboard parts to allow the audio into the Echo Board without the headaches and the "other side" (output) of the parts would be the continuation of the audio path from the Mic into the rest of that radio.

    You chose the more dedicated route of the Cobra 25 - you should be ok in that scenario.

    But, I'm only letting you know that they threw you a curve by having the radios' Mic get power from the radio thru the audio line to power the element. This method was so they can save $$$ by not having to have a ton of support parts for the mic amp and limiter tie ins' - just the Electret gives enough power to drive an audio amp directly - kinda' like a turntable - Magnetic Cartridge requires PHONO input amp (low level) while Ceramic Cartridge gives you Line-Level (Tape Monitor) output. Why fuss with all that low-level amp stuff when you can just run a power mic on a 3V power source using an Electret instead.

    Good luck on your project.
     
  12. Cutlass327

    Cutlass327 Member

    Joined:
    May 1, 2016
    Messages:
    48
    Likes Received:
    12
    That would make sense. Thank you for the follow-up.
     
  13. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    1,946
    Likes Received:
    1,377
    That's what this world needs. An echo board with support for electret mikes on its input side.

    73
     
    Shadetree Mechanic likes this.

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!