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RCI 2970N4 Amp Switch ?

Discussion in 'CB and Export Equipment and Accessories' started by bevis, Jun 12, 2021.

  1. bevis

    bevis New Member

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    Does anyone know how the typical amp switch mod is done on the 2970N4 ? Its the non colorized model.
    I bought a new in the box 2017 model and Bells has their card inside with the radios wattage as tested.
    The person that I bought the radio from did not have the amp off switch mod done to it so it could be used with a low drive amp and for just barefoot talking local. I have searched the web for a couple of hours and coming up with a blank. Its a new radio thats never been turned on and i dont want to do the mod incorrectly. I see the Bells vids where they are installing a mini toggle switch that appears to not be switching very much current and it appears to work well for them. Any help on this specific model mod would be appreciated.
    Thanks in advance.


     
    #1 bevis, Jun 12, 2021
    Last edited: Jun 12, 2021

  2. Ranch55

    Ranch55 Sr. Member

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    Yes, easy to do......
     
  3. bevis

    bevis New Member

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    Could you elaborate on the process please ?
     
  4. Ranch55

    Ranch55 Sr. Member

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    Well, I am currently looking to see if I can find a photo .......
    Standby ......
     
  5. Ranch55

    Ranch55 Sr. Member

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    Can you see the mirror board at the top right in the first photo ?
    Yellow wire and green wire running to a plug on the board just above the mirror board.
    Generally, if you cut the green wire, and splice the on/off switch into that wire, it will turn off the power to engage the the small relay on the amplifier board.
    The radio will operate normally on low power without the amplifier.
    These photos are the inside of a Ranger RCI-2995DXCF, but the main PCB is the same as the 2970N4 .....

    [​IMG]


    [​IMG]


    [​IMG]

    [​IMG]
     
  6. Ranch55

    Ranch55 Sr. Member

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    Use a mini ON/OFF switch .......
    If I remember correctly, on a 2970N4, the wires are brown and black ......
    Splice into the brown wire ......
     
  7. bevis

    bevis New Member

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    Thank you so much !!!!!!!!!!!
    Great pics
     
    Slowmover likes this.
  8. bevis

    bevis New Member

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    I also have a virgin 2995DX that could use the same amp cut off mod. Is the wiring color the same in the 2995dx as the 2995dxcf ?
     
  9. Ranch55

    Ranch55 Sr. Member

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    probably......
    But they are the same wires in the same location.
     
  10. bevis

    bevis New Member

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    thanks for all the great help.
    just to make sure im understanding this correctly, you are not killing the power to the amp but the relay that feeds the amp, correct ? Im just making sure i understand what im doing.
     
  11. NightThumper

    NightThumper Sr. Member

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    Yes, I just did one on my Galaxy DX98VHP. Mine was a blue wire yours is the brown. The switch cuts power to the amp section. Mine now dead keys .5 to roughly 10 and swings to 42 watts without the amp section. When the amp switch is turned on PEP AM is 290ish.

    Be very careful not to get metal shavings inside your radio. I used a piece of duct tape inside folded back with the sticky side up. I did the same thing on the outside. This caught all the metal shavings. Not many fall inside since your drilling the hole from the outside. Go SLOW…VERY SLOW when drilling the hole.

    Measure your wire length to the switch carefully sometimes there’s just barely enough. If the wires you need are under that long (1.5-2 inch)RF blocking shield that is slid into place between 3 pinch clips, you can gentle pull that out…sometimes the wires are routed underneath that.

    Brad
     
    #11 NightThumper, Jun 13, 2021
    Last edited: Jun 14, 2021
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  12. Ranch55

    Ranch55 Sr. Member

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    Well, Brad...... Good Morning.
    No, this procedure does not cut power to the amplifier section.
    What this does is cut the electrical DC voltage to the relay on the amp board.
    EDIT: It doesn't actually cut the DC voltage to the relay, it cuts the signal to the transistor that goes to ground to key the relay....
    This prevents the relay engaging, which in turn prevents the RF power from the radio entering the amplifier section.
    The radio RF power just passes through the unkeyed relay straight to the antenna out connector.
    Hope this explanation helps ......
     
    #12 Ranch55, Jun 14, 2021
    Last edited: Jun 14, 2021
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  13. Ranch55

    Ranch55 Sr. Member

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    Yes, that is correct.
     
  14. NightThumper

    NightThumper Sr. Member

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    I should have been more precise instead of stating it cut the power to the amp section. Good clarification my friend.
     
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