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Uniden president ssb base no transmit and no receive how to fix

I have no Recive No Transmitt No signal on meter How to fix

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  • Greg L Schulz
    Greg L Schulz Apr 24, 2012

    Hmmm it is a Uniden Base just says President on it chkd Mic is ok no trans or receive but hooked up another radio and thru dummy load it has modulation when keyed no meter readings tho on trans or recive

  • Greg L Schulz
    Greg L Schulz Apr 24, 2012

    O....................K #1 It is a 8719 chip #2 got receive now thanks Found solder bad on ic mod chip No transmitt tho and no meter movement on receive or transmitt but on dummy load and extra radio can hear mod on extra rig on transmitt Possible finals? and what about no meter movement

  • Greg L Schulz
    Greg L Schulz Apr 24, 2012

    No Radio has not been modified at all the cans are all still sealed and Receive is back but no Transmitt and is on reg channals receives great now but still no trans on am or sideband and no meter movement at all

  • Greg L Schulz
    Greg L Schulz Apr 25, 2012

    Hmmmm any idea where I can find the replacement final and driver? I beleve its a 1306 an 1307 Don,t think they stock those anymore

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  • Master
  • 14,553 Answers

Have the mic checked first to make sure wired correctly and or wires not broken where connect to plug----also check to see if same on SSB and Am.

President what? Madison, Lincoln etc.

Posted on Apr 24, 2012

  • 3 more comments 
  • SD Tech
    SD Tech Apr 24, 2012

    will be on plate on rear which it is---not front.

    As old as it is first issue is this one or two problems--I would begin by checking the voltage regulator and other chips that are bolted to the sidewalls of the radio--it is not uncommon for the folded over pins to break loose and just need soldering.(audio chip if it has it--should be there can cause this.)

    Then quickly with unit off and not powered test the driver and final to see if open or shorted---There are a few other possible reasons---some of the real old ones use a UPC1148 or a number like that for the audio output---no sound will equal no audio at speaker but if it modulates that is likely good--follow the suggestions and let me know what happens.

  • SD Tech
    SD Tech Apr 24, 2012

    By the way--what PLL chip is used? 858?

  • SD Tech
    SD Tech Apr 24, 2012

    has the mb8719 been "altered" ? what you could have is it is not when showing 19 etc there but somewhere else----like way up or down and actually on another freq.

    If not modified final will not kill receive---keep looking--find one bad connection you may find more---if it has been modified for extra channels there will be leads soldered to pins on that PLL---inspect them to make sure not broken loose etc.

  • SD Tech
    SD Tech Apr 24, 2012

    check driver and final (they are base-collector-emmiter) and should have dc when keyed on middle pin---ohm them (may have to unsolder all leads) to be sure not open or shorted----you know how?

    If one is open or shorted replace both---radio has a AM reg transmit transistor but ssb would still function and transmit even with that bad---not a bad idea with no power to read from center pin on either driver or final to the board ground--cans etc---no short there can exist---metal frame of radio is a different ground.

  • SD Tech
    SD Tech Apr 25, 2012

    there are replacements but not as high a output--call for example Suburban Electronics with the generic numbers on the two and they will have replacements--can also google the generic to see which replace them--think one is 2sc2166 ---number on original will be 2sc1307?

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Benimur
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SOURCE: No Modulation!!

Hi,

Most modulation problem could be traced to:
1. mic or the cable and/or the mic connector;
2. AMC (amplitude modulation control) - it's a single transistor that regulates modulation and occasionally has been known to clamped on the mic audio;
3. the AM/SSB switch - spraying with contact cleaner is a temporary remedy; and/or
4. audio amp - however if your receive audio is good, then this does not apply.

Hope this be of initial help/idea. Without a model number, I can't be more specific as to component(s) or PCB location but pls post back for any developments (or lack thereof) or should you need additional information.

Good luck and kindest regards.

Posted on Feb 09, 2008

SOURCE: No AM carrier or modulation. SSB transmits good

Great now check TR42 AM POWER then check TR41 AM POWER REG. They are on right side twards rear of board with front of radio faceing you part side up. A good place to start!

Posted on Jul 07, 2007

Shuttle83
  • 1139 Answers

SOURCE: president mckinly ssb/am model with mb8719 pll chip.

It looks like you had some loose connections in that CB. you may want to also check for other cold solder joints throughout the units and touch them up with some solder. Might I suggest you use a desoldering tool and then just add new solder to the connection.

Posted on Sep 05, 2007

  • 32 Answers

SOURCE: uniden president grant stops transmitting

this sounds like the AM regulator has lost All of its smoke.(thats what electronic parts are made of) If this is A Grant the AM regulator is located in the rear right hand side of the radio.If it is a grant XL this is located on the very back of the radio on its on little circuit board.check this part part to see if is your problem.one other way that you can tell if this is the problem when it stop transmitting check it on side band (LSB or USB) to see if it transmitt.If it does that is most likley your problem.

Posted on Feb 02, 2009

  • 219 Answers

SOURCE: uniden grant ssb cb, receives but no transmit,

test your voltage regulator and make sure you don't have a bad crystal

Posted on Dec 16, 2009

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