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T2-135 going deaf

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  • Bob Poortinga
    After almost 3 years of faithful service, my T2-135 has gone deaf. Not completely deaf, just mostly deaf. When first installed it decoded most everything it
    Message 1 of 5 , Aug 25, 2010
      After almost 3 years of faithful service, my T2-135 has gone deaf. Not
      completely deaf, just mostly deaf. When first installed it decoded most
      everything it heard. Now it only decodes the strongest, clearest signals.
      For example, after a two week round trip from Indiana to Colorado, it added
      about 25 stations to my Nuvi. I would normally get at least a couple of
      hundred stations. This is becoming problematic because it really interferes
      with the ability to send and receive APRS messages.

      I have tried removing the radio from the car and attaching it to a base
      antenna and power supply with no difference in decoding ability observed.
      I know the radio is receiving properly becuase I can see the S-meter jump
      and hear the audio when not in digital mode. I have also updated the
      firmware which made no difference.

      This is a version 2.1 model. Is there an input cap on this thing that
      might have gone bad? Is there anything else that might be causing this
      issue? Should I just consider it's time to replace a 3 year old piece
      of equipment?

      --
      Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
      Bloomington, Indiana US
    • Randy Love
      First things first, have you tried reseating the connectors? IIRC, that is no positive latching of the connector to the radio board. Give that a shot. 73,
      Message 2 of 5 , Aug 25, 2010
        First things first, have you tried reseating the connectors?

        IIRC, that is no positive latching of the connector to the radio board.

        Give that a shot.

        73,
        Randy
        WF5X

        On Wed, Aug 25, 2010 at 1:25 PM, Bob Poortinga <bobp+yahoo@...> wrote:
         

        After almost 3 years of faithful service, my T2-135 has gone deaf. Not
        completely deaf, just mostly deaf. When first installed it decoded most
        everything it heard. Now it only decodes the strongest, clearest signals.
        For example, after a two week round trip from Indiana to Colorado, it added
        about 25 stations to my Nuvi. I would normally get at least a couple of
        hundred stations. This is becoming problematic because it really interferes
        with the ability to send and receive APRS messages.

        I have tried removing the radio from the car and attaching it to a base
        antenna and power supply with no difference in decoding ability observed.
        I know the radio is receiving properly becuase I can see the S-meter jump
        and hear the audio when not in digital mode. I have also updated the
        firmware which made no difference.

        This is a version 2.1 model. Is there an input cap on this thing that
        might have gone bad? Is there anything else that might be causing this
        issue? Should I just consider it's time to replace a 3 year old piece
        of equipment?

        --
        Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
        Bloomington, Indiana US


      • Matthias Granberry
        While I don t actually have a T2, the pictures don t make it look like there are any electrolytic caps to go bad. I d pull the board out and follow the trace
        Message 3 of 5 , Aug 25, 2010
          While I don't actually have a T2, the pictures don't make it look like there are any electrolytic caps to go bad.  I'd pull the board out and follow the trace from pin 3 on the radio connection to the modem IC.  There is a whole mess of .1 and .027 uF caps, probably of the ceramic variety, but I doubt that's your problem.  I suspect it's a cold solder joint or a place where the modem has worked itself loose after 3 years of thermal expansion/contraction cycles in a hot car.  I'd hook it up to a radio and use a toothpick pr plastic tooth flosser (the pointy end) to lightly press on each of the pins to see if it wakes the device up.
           
          On Aug 25, 2010, at 12:25 PM, Bob Poortinga wrote:

           

          After almost 3 years of faithful service, my T2-135 has gone deaf. Not
          completely deaf, just mostly deaf. When first installed it decoded most
          everything it heard. Now it only decodes the strongest, clearest signals.
          For example, after a two week round trip from Indiana to Colorado, it added
          about 25 stations to my Nuvi. I would normally get at least a couple of
          hundred stations. This is becoming problematic because it really interferes
          with the ability to send and receive APRS messages.

          I have tried removing the radio from the car and attaching it to a base
          antenna and power supply with no difference in decoding ability observed.
          I know the radio is receiving properly becuase I can see the S-meter jump
          and hear the audio when not in digital mode. I have also updated the
          firmware which made no difference.

          This is a version 2.1 model. Is there an input cap on this thing that
          might have gone bad? Is there anything else that might be causing this
          issue? Should I just consider it's time to replace a 3 year old piece
          of equipment?

          --
          Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
          Bloomington, Indiana US


        • Bob Poortinga
          ... Yes, no joy. -- Bob Poortinga K9SQL Bloomington, Indiana US
          Message 4 of 5 , Aug 25, 2010
            Randy WF5X asks:

            > First things first, have you tried reseating the connectors?

            Yes, no joy.

            --
            Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
            Bloomington, Indiana US
          • Bob Poortinga
            ... I wish to report that I had a fellow ham in the area (who is an electronics tech and repairs surface mount PCBs) look at the board. He found a number of
            Message 5 of 5 , Oct 14, 2010
              On Wed, Aug 25, 2010 at 12:40:31PM -0500, Matthias Granberry wrote:

              > I suspect it's a cold solder joint or a place where the modem has worked
              > itself loose after 3 years of thermal expansion/contraction cycles in a
              > hot car.

              I wish to report that I had a fellow ham in the area (who is an electronics
              tech and repairs surface mount PCBs) look at the board. He found a number
              of poor solder joints and re-flowed the whole board. It now works like a
              champ! This is one of the early T2-135s and I believe Scott had problems
              with the quality of assembly done by this particular sub-contractor.

              73 de
              --
              Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
              Bloomington, Indiana US
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