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Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

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  • Joe Vilardo
    Alan I found one error, R39 & R40 reversed. I get 80ma now in the transmit mode. R48=0 & R49=3.1mv R39 =3.15 volts with PTT active. NO PTT R38=0, R40=0,
    Message 1 of 12 , Jan 19, 2013
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      Alan
       
      I found one error, R39 & R40 reversed.  I get 80ma now in the transmit mode.  R48=0 & R49=3.1mv  R39 =3.15 volts with PTT active.
      NO PTT R38=0, R40=0, R41=0  PTT ON R38=2.5V, R40=1.68V, R41=.65V.
      12 volts supply = 12.6V
       
      Joe
       
      From: Alan
      Sent: Saturday, January 19, 2013 10:18 AM
      Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble
       
       


      ----- Original Message -----
      Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

      >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
      >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

      Joe

      All low. Sorry I should have asked for R39 hairpin as well.
      If that is not around 12V then check it's value.
      And check S12V.
      Check all solder joints around Q5 and the other components mentioned.

      73 Alan G4ZFQ

      >
      > I ran the current test for receive and TX; Receive is right in the game at 25 ma but in tansmit I only get 60 ma not the 125ma
      > expected.
      >
      > voltage drop accross R48 = 3mv, R49=3mv, hairpin R46 to gnd = 0.4mv,
      > hairpin R35(PTT ACTIVE)to grnd 12.36V, hairpin R35 (NO PTT)=0
      >

      Joe,

      I think the test voltages you got are lower than anyone has reported but I'd think that if they were all the same you would still
      get the correct R48/9 voltages. (Reason for low current readings).
      Please measure the voltages at R38, 39, 40, 41 which may give a clue.
      Measure the resistance to ground at R46 hairpin. (Power off)
      Check the soldering and look for splashes or even whiskers of PCB that have been left after manufacture.

      73 Alan G4ZFQ

    • Alan
      ... Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble ... NO PTT R38=0, R40=0, R41=0 PTT ON R38=2.5V, R40=1.68V, R41=.65V. 12 volts
      Message 2 of 12 , Jan 19, 2013
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        ----- Original Message -----
        Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble


        >I found one error, R39 & R40 reversed. I get 80ma now in the transmit mode. R48=0 & R49=3.1mv R39 =3.15 volts with PTT active.
        NO PTT R38=0, R40=0, R41=0 PTT ON R38=2.5V, R40=1.68V, R41=.65V.
        12 volts supply = 12.6V

        Joe

        Getting closer.
        Check that R47 hairpin and the gates of Q7,8 are all at 2V5, the same as R38.
        Check you have about 12V on the primary of T4 and Q7,8 drains.

        73 Alan G4ZFQ

        Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

        >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
        >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

        All low. Sorry I should have asked for R39 hairpin as well.
        If that is not around 12V then check it's value.
        And check S12V.
        Check all solder joints around Q5 and the other components mentioned.
      • Joe Vilardo
        From: Alan Sent: Sunday, January 20, 2013 2:13 AM To: softrock40@yahoogroups.com Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble ...
        Message 3 of 12 , Jan 21, 2013
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          From: Alan
          Sent: Sunday, January 20, 2013 2:13 AM
          Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble
           
           


          ----- Original Message -----
          Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

          >I found one error, R39 & R40 reversed. I get 80ma now in the transmit mode. R48=0 & R49=3.1mv R39 =3.15 volts with PTT active.
          NO PTT R38=0, R40=0, R41=0 PTT ON R38=2.5V, R40=1.68V, R41=.65V.
          12 volts supply = 12.6V

          Joe

          Getting closer.
          Check that R47 hairpin and the gates of Q7,8 are all at 2V5, the same as R38.
          Check you have about 12V on the primary of T4 and Q7,8 drains.

          73 Alan G4ZFQ

          ALAN

          This is what I measured:

          R47=2.54, Gate of Q7,Q8=2.54, R38=2.52, Drain of Q7,Q8=12.64. T4-P1,P2=12.64

           

          Thanks,

          Joe



          Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

          >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
          >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

          All low. Sorry I should have asked for R39 hairpin as well.
          If that is not around 12V then check it's value.
          And check S12V.
          Check all solder joints around Q5 and the other components mentioned.

        • Alan
          ... Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble ... Check you have about 12V on the primary of T4 and Q7,8 drains. ... Joe, I
          Message 4 of 12 , Jan 21, 2013
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            ----- Original Message -----
            Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble




            >>Check that R47 hairpin and the gates of Q7,8 are all at 2V5, the same as R38.
            Check you have about 12V on the primary of T4 and Q7,8 drains.

            >This is what I measured:

            >R47=2.54, Gate of Q7,Q8=2.54, R38=2.52, Drain of Q7,Q8=12.64. T4-P1,P2=12.64


            Joe,

            I wondered if that would be your reply.
            All seems correct except that Q7,8 are not conducting.
            Are they the correct way round?
            Otherwise they seem suspect which is strange as they were tested when you did the balance check. But they are sensitive to static.
            Unless someone else has any ideas I'd suggest replacing them.

            73 Alan G4ZFQ



            Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

            >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
            >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

            All low. Sorry I should have asked for R39 hairpin as well.
            If that is not around 12V then check it's value.
            And check S12V.
            Check all solder joints around Q5 and the other components mentioned.
          • Joe Vilardo
            Alan I removed Q7 and Q8, re-tested them and they were both gone, must have been static, I didn’t use my wrist straps until I was installing Q7 and Q8. I
            Message 5 of 12 , Jan 21, 2013
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              Alan
               
              I removed Q7 and Q8, re-tested them and they were both gone, must have been static, I didn’t use my wrist straps until I was installing Q7 and Q8. I think I zapped them when I was shaping them for the 90 degree fit on the board, that’s when I didn’t have the wrist straps on.
               
              I had two remaining BS170’s one tested 2.98 V while the other was 2.01 V and I decided to install them even though there was a difference in their test voltage.  When I key the TXRX Ensemble now I get 115 ma of current draw on the 13.8 volt supply to the board. The measured drop across R48=40.1mv and R49=50.2mv   Is this variation acceptable? or should I look for 3 more that are closer to each other. I assume that if they tested closer in value then the drop between R48 and R49 would be closer as well?
               
              Alan, thanks for your remote trouble shooting and guiding hand.
              Joe
              From: Alan
              Sent: Monday, January 21, 2013 2:02 PM
              Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble
               
               


              ----- Original Message -----
              Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

              >>Check that R47 hairpin and the gates of Q7,8 are all at 2V5, the same as R38.
              Check you have about 12V on the primary of T4 and Q7,8 drains.

              >This is what I measured:

              >R47=2.54, Gate of Q7,Q8=2.54, R38=2.52, Drain of Q7,Q8=12.64. T4-P1,P2=12.64

              Joe,

              I wondered if that would be your reply.
              All seems correct except that Q7,8 are not conducting.
              Are they the correct way round?
              Otherwise they seem suspect which is strange as they were tested when you did the balance check. But they are sensitive to static.
              Unless someone else has any ideas I'd suggest replacing them.

              73 Alan G4ZFQ

              Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

              >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
              >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

              All low. Sorry I should have asked for R39 hairpin as well.
              If that is not around 12V then check it's value.
              And check S12V.
              Check all solder joints around Q5 and the other components mentioned.

            • Joe Vilardo
              Alan Correction to the previous note. The remaining 2 BS170 when tested measured 1.98 not 2.98 V and 2.01 Volts. Joe From: Joe Vilardo Sent: Monday, January
              Message 6 of 12 , Jan 21, 2013
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                Alan
                 
                Correction to the previous note.  The remaining 2 BS170 when tested measured 1.98 not 2.98 V and 2.01 Volts.
                 
                Joe
                 
                Sent: Monday, January 21, 2013 6:33 PM
                Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble
                 
                 

                Alan
                 
                I removed Q7 and Q8, re-tested them and they were both gone, must have been static, I didn’t use my wrist straps until I was installing Q7 and Q8. I think I zapped them when I was shaping them for the 90 degree fit on the board, that’s when I didn’t have the wrist straps on.
                 
                I had two remaining BS170’s one tested 2.98 V while the other was 2.01 V and I decided to install them even though there was a difference in their test voltage.  When I key the TXRX Ensemble now I get 115 ma of current draw on the 13.8 volt supply to the board. The measured drop across R48=40.1mv and R49=50.2mv   Is this variation acceptable? or should I look for 3 more that are closer to each other. I assume that if they tested closer in value then the drop between R48 and R49 would be closer as well?
                 
                Alan, thanks for your remote trouble shooting and guiding hand.
                Joe
                From: Alan
                Sent: Monday, January 21, 2013 2:02 PM
                Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble
                 
                 


                ----- Original Message -----
                Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

                >>Check that R47 hairpin and the gates of Q7,8 are all at 2V5, the same as R38.
                Check you have about 12V on the primary of T4 and Q7,8 drains.

                >This is what I measured:

                >R47=2.54, Gate of Q7,Q8=2.54, R38=2.52, Drain of Q7,Q8=12.64. T4-P1,P2=12.64

                Joe,

                I wondered if that would be your reply.
                All seems correct except that Q7,8 are not conducting.
                Are they the correct way round?
                Otherwise they seem suspect which is strange as they were tested when you did the balance check. But they are sensitive to static.
                Unless someone else has any ideas I'd suggest replacing them.

                73 Alan G4ZFQ

                Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble

                >I re-checked voltage drop across R48 and R49. R48=0, R49=2.9. The following voltages to ground: NO PTT R38=0.2mv,R39=0.1mv,
                >R40=0.1mv,R41=0.0mv PTT ON R38=1.1V , R39=1.6V, R40 =1.02V, R41=0.1mv. R46 resistance to gnd=2430 ohms.

                All low. Sorry I should have asked for R39 hairpin as well.
                If that is not around 12V then check it's value.
                And check S12V.
                Check all solder joints around Q5 and the other components mentioned.

              • Alan
                ... Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble ... Joe Glad that got sorted out! very strange both BS170s failed. Yes the R48/49
                Message 7 of 12 , Jan 21, 2013
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                  ----- Original Message -----
                  Subject: Re: [softrock40] Trouble with Transmitter section RXTX Ensemble


                  >Correction to the previous note. The remaining 2 BS170 when tested measured 1.98 not 2.98 V and 2.01 Volts.

                  Joe

                  Glad that got sorted out! very strange both BS170s failed.
                  Yes the R48/49 volts are quite acceptable.


                  73 Alan G4ZFQ


                  >I removed Q7 and Q8, re-tested them and they were both gone, must have been static, I didn’t use my wrist straps until I was
                  >installing Q7 and Q8. I think I zapped them when I was shaping them for the 90 degree fit on the board, that’s when I didn’t have
                  >the wrist straps on.

                  I had two remaining BS170’s one tested 2.98 V while the other was 2.01 V and I decided to install them even though there was a
                  difference in their test voltage. When I key the TXRX Ensemble now I get 115 ma of current draw on the 13.8 volt supply to the
                  board. The measured drop across R48=40.1mv and R49=50.2mv Is this variation acceptable? or should I look for 3 more that are
                  closer to each other. I assume that if they tested closer in value then the drop between R48 and R49 would be closer as well?
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