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Uniden PC-76 Hi-Fi mods

Discussion in 'CB Radio Modifications' started by 350GA, Feb 7, 2020.

  1. 350GA

    350GA Member

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    Good afternoon everyone.



    Does anyone happen to have the capacitor locations and values to widen up the TX & RX audio on the PC-76? I have been searching all over with no luck. Thanks in advance!
     

  2. 350GA

    350GA Member

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    Anyone? Goldfinger possibly?
     
  3. 711

    711 Well-Known Member

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    the problem is the lack of schematics to call out part numbers to change. So you'll have to do a side by side comparison against a 29 for the part numbers. Match the 29 location to your 76 and swap.

    From GF forum:
    Cobra 29LX with the TDA2003 audio chip

    Receive:
    Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar
    Change C48to a 1000uF, 25 volt Electrolytic, observe polarity

    Transmit:
    Change C69 to a .001uF disc
    Change C68 to a 1.5uF Tantalum with the + side towards the right (audio chip) side of the radio.
    Change C37 to a .1uF mylar (or parallel a second .033uF mylar with the existing one)


    Cobra 29LTD with the TA7222AP audio chip

    Receive:
    Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar
    More highs?: remove C204 (some year ranges don't have this cap)

    Transmit:
    Change C69 to a .001uF disc
    Change C68 to a 1uF Tantalum (some radio's already have a 1uF in them)
    Change C37 to a .068uF mylar (or parallel a second .033uF mylar with the existing one)


    New 2010/2011 Cobra 29LTD (TDA2003 audio chip)

    Receive:
    Remove C170
    Change C33 and C40 to 2.2uF non-polarized electrolytic or mylar

    Transmit:
    Change C68 to a 1.5uF tantalum with the + side towards the right (audio chip) side of the radio.
    Change C69 and C125 to .001uF disc
    Change C37 and C43 to .1uF mylar

    29.png
     
    #3 711, Feb 10, 2020 at 10:10 PM
    Last edited: Feb 10, 2020 at 10:23 PM
  4. 9C1Driver

    9C1Driver Sr. Member

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    And in the end what is it really going to do for you? Not much. Let your PC76 be what it was intended to be, a very nice talking cb radio.
     
  5. 711

    711 Well-Known Member

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    We are in the modifications section of the forum. Sheesh
     
  6. 350GA

    350GA Member

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    Thank you 711! I realized that after doing some more research that they are in the same locations as a Cobra 29, just labeled different.

    And I personally LOVE the cap mods on the RX side. It makes a big difference in the receive audio quality and helps reduce the white noise hiss. Granted I use different cap values than what Goldfinger recommends to get a particular sound I like, but they work great! Thanks!
     
    543_Dallas likes this.
  7. 711

    711 Well-Known Member

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    Welcome , I like the receive after swapping caps. So easily done and makes listening more enjoyable. Glad it worked for you
     
    350GA likes this.

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